This is what I think release schedule will be based on rumors and speculation. Tried to specify what was rumor and what was speculation.
2020:
Black Widow- Not sure when it would take place. There have been rumors for a while suggesting a prequel, pre-Iron Man 2. Sebastian Stan did recently just suggest it would be right after Civil War, though. Maybe he worded it wrong or was mistaken, but whatever the case may be in terms of time period, I do think the plot will revolve around Black Widow's origin in some way, even if it is flashbacks. Perhaps a new Black Widow will be introduced? Rumors have been saying that too.
(DISNEY+) Falcon and the Winter Soldier- Post Endgame. Rumors suggest SHIELD (Nick Fury?) recruit our titular heroes to take down Hydra (who are apparently targeting the UN). I would guess it will expand and grow the friendship of Sam and Bucky. Also delve into Sam's struggles to become new Captain America. US Agent, or at least a character like him, introduced reportedly. Becomes main villain since he is government's choice to be Captain America. Political and espionage thriller in same vein as Winter Soldier. Sharon Carter to return, same with Zemo who will probably introduce conflict with Bucky.
The Eternals- Will set up a whole new layer of history and depth not just to the cosmic universe but the Marvel universe in general. Takes place over the course of millions of years. Epic in scope. Eternals vs. Deviants, but with the main conflict dealing with rogue Eternals (Druig, rumored to be played by Keanu Reeves) and humans on Earth. Rumors suggest a young Odin in a smaller role, maybe we also see the return of Bor? Grand intergalactic wars inbound. First gay superhero lead with either Hercules or Ikaris.
2021:
Black Panther 2- Political in nature, especially because I am sure it will deal with other countries that are not so happy with Wakanda's newfound presence in the world stage. Maybe show how some countries can't handle a new world superpower? I don't know how realpolitik it will get, but rumors suggest an appearance of Killmonger in the spiritual place, and Queen Divine Justice as a villain. Some popular fan speculation has Doom leading Latveria against Wakanda, or Namor leading Atlantis. Would welcome either of those!
Shang-Chi - Not much is known, but I expect it to mainly take place in China with globetrotting around the world (potentially New York and London). I think some cameos from other Marvel characters would be cool, like Doctor Strange, Ancient One (if it is a prequel), or Black Panther. Rumors have the Mandarin being his traditionally villainous father, rather than the problematic and rather racist character of Fu Manchu. Recent comments by Kevin Feige add fuel to the fire when he said that there were plans for the real Mandarin (teased in the Hail to the King One Shot) in the future.
(Disney+) WandaVision - Rumors have the show revolve around Wanda living with a resurrected Vision in the suburbs trying to give him a soul and live a normal life. Met with opposition by the community for their unconventional relationship (robosexuality basically). Vision eventually gets possessed and turns evil apparently, and villain may be old Kirby character of Agatha Harkness. 1950s suburban aesthetic with a psychological thriller tone.
Spider-Man Far From Home sequel - Rumors suggest (without getting into FFH spoilers) a possible Sinister Six film. But these rumors come from less certifiable sources... so I don't know. But I do think 2021 will be first year to have four Marvel theatrical releases, as this film will be obviously filmed and produced heavily by Sony so I think Marvel will test the four per year waters in 2021. The new Disney release schedule (which can always be subject to change) says three Marvel films for 2021, but I don't think it is including a Sony film.
(Disney+) Loki - Rumors are split. On one hand, we have camp that has been saying (especially since Endgame has come out) that the show would revolve around the 2012 Loki in the alternate timelines where he escapes with the Tesseract. However, rumors from both before and after the release of Endgame say it would be about a young Loki, with Hiddleston playing the role in some present day scenes. It would follow his adventures and schemes throughout the Nine Realms growing up. Some rumors have Rene Russo taking on a role in the series, and that the present day scenes with Hiddleston would have him trying to negotiate his fate in the afterlife with the gods of the underworld.
Doctor Strange 2 - Rumors say characters from first one will return (Palmer, Mordo, Ancient One, Wong) and that at least part of it will be set in the 1980s (probably explaining return of Ancient One). Rumors of Mordo, Nightmare, and Brother Voodoo as villains (with Mordo as more of a sympathetic Loki-type villain). Other rumors suggest appearance of Namor, though I'm wary of these since they seem to have conveniently popped up around the time Scott Derrickson tweeted a picture of Strange and Namor in a comic. Classic Doctor Strange character Clea to appear, portrayed by Asian actress.
2022:
Captain Marvel 2 - Not really any rumors for this. Considering this will be the first cosmic Marvel film created and released post-Fox merger (Eternals was in post production before merger, and same with Guardians 3), I'm willing to bet we will see appearances or at least mentions of some major galactic players for the first time that were previously under the Fox umbrella. I can see the Super Skrull and Silver Surfer possibly having a role, and maybe Galactus. I am iffy on whether or not we will ever see a Nova film, though rumors and hints by Marvel Studios creatives have suggested his eventual appearance in a film, so maybe we see Richard Rider here? And then his actual film revolves around his death and passing the mantle to Sam Alexander (due to events of Infinity War?). As far as Carol herself, prequel or not I think the movie will revolve around her helping end the Skrull-Kree war and expand on her character, including challenging her not just physically but mentally, as her greatest strengths become her weaknesses. Maybe some Skrulls turn out to be evil and it complicates her allegiances?
Guardians of the Galaxy Vol. 3 - Lots of trustworthy and substantial rumors for this. Villain is High Evolutionary. He is involved in origin of Rocket, and the film would delve into that more. Introduction of his otter-like love interest Lylla. Quill and Nebula looking for 2014 Gamora, they grow closer (presumably as friends). I would think part of plot is Quill trying to get her to fall for him again, but it doesn't work out...maybeeee him and Nebula fall for each other instead? I can see maybe plot point of the High Evolutionary reverting Nebula to her natural state without the cybernetics? Also rumors of Adam Warlock, and Drax finding out his daughter is alive. Beta Ray Bill reportedly meets Thor for first time. As far as my speculation, I think Ravagers will also figure in and I think they will re-introduce the OG comics Guardians 3000 crew with Stallone, and that this film (per Gunn's hints) will provide closure for the OG Guardians crew and usher in a new era of the Guardians of the Galaxy, maybe consisting of Warlock (Zac Effron anyone?), Thor, Beta Ray Bill, maybe some others?
Ant-Man and the Wasp sequel - No rumors for this. I think some type of story revolving around exploration of the microverse will be featured, after teasing micro-worlds in the previous film. Should have Pym, Janet, and Miguel's crew should return. Maybe Foster and Ghost. Maybe something will happen to her that will lead to her inclusion in a Thunderbolts films (more on that later in schedule...) I also think the now teenage Cassie will be a major part of the movie, maybe we will see her rise to the role of Stature. Other than that, the villain and overall plot can really be anything, and I hope it is more creative (especially visually) than the previous film was, IMO.
(Disney+) TBD - I think another Disney+ show will premiere in 2022 but I'm not sure what. Rumors suggest Hawkeye as of now, but I honestly think that is up in air and depends on what Jeremy Renner wants to do post-Endgame. If not this, then there has been a Lady Sif show rumored, which would be cool if they want to reintroduce the character in the what will have been almost 10 years since 2013's Thor: The Dark World. Potentially leading into a Thor 4? If not that, there are floating rumors and hearsay of a War Machine show, Rocket show, with maybe Groot. Also there is always possibility of a sequel season to Falcon and Winter Soldier, or WandaVision.
2023:
**2023 I think things get a bit harder to determine. I DO think it will be first year since Endgame to include some type of team-up film(s).**
Thunderbolts - Rumored line-up of Zemo, Abomination, Justin Hammer, Ghost. Antagonist is the Leader. I would also like to see Songbird since she is an OG and would add more diversity to the team. Secretary "Thunderbolt" Ross would be the "Nick Fury" of the team?
Avengers sequel/spiritual sequel - Return of the Avengers in the films, probably would feature main roster of the new guard (Spider-Man, Cap Marvel, Black Panther, Shang-Chi, Doctor Strange, Captain "Falcon" America). I would assume Bucky, Ant-Man, Wasp and Hulk will feature, but I'm not sure if the film's Avenger roster would get a bit too crowded at that point, especially if they face the Thunderbolts like I think they might. I think the threat will be more grounded, though it could be someone else like maybe Norman Osbourne. In that case, I could see the roster being different if they make it more grounded, like say Spidey, Black Panther, Cap Falcon, Wasp, Ant-Man, Shang-Chi, Hulk, Bucky...maybe Doctor Strange? Hawkeye presumably retired, Wanda and Vision trying to live normal life? I dunno, nailing the roster may be tricky. I don't even know what the villain would be, but I do think it won't be cosmic, and really at the end of the day the priority of the film should be to build chemistry between our heroes like Strange, Spidey, Cap Marvel, Cap Falcon, Black Panther etc so that they become as close as the OG Avengers did.
Thor 4 - Rumors say this film is in development, and I'm sure Taika is very willing to eventually come back and helm another film. Not sure if it would happen in 2023, but I think Marvel is heading towards some type of cosmic team-up film, and this could help lead into that. I would assume return of Valkryie, New Asgard, Korg, and the gang. I do think I read something at one point (forget source and whether or not it was credible) that suggested the movie would feature the return of Hela in some form.
Another Disney+ show - who knows what it would be this far out lol for all we know Disney+ or at least the Marvel shows are a failure at this point and they don't release anything. Probably not, but even then any show releasing this year would just be pure conjecture on my part.
Spidey 4 - I think Sony is going to like having Spider-Man releasing same year as Avengers films, and this would also follow the pattern so far of a Spidey film releasing every two years. Who knows what the film would be about, but if the last one isn't about the Sinister Six, then I think this one most definitely will. I also think this will be the film to have Peter finishing up high school.
2024:
Cosmic team-up film - Like an Avengers movie but in space basically. Feature Guardians, Thor, Nova, Cap Marvel, etc. No rumors for this, but I do think it is likely and fits with Feige hinting he would like to see more team up films beyond just the standard Avengers team ups. Possibly hint or even fully feature Galactus, Annihilus, and/or another cosmic villain. I assume Eternals would figure into it, if not in this film then maybe in the Avengers or Captain Marvel movie.
Black Knight (and Captain Britain maybe) - He's been rumored heavily, but I struggle to find an earlier spot for him unless Marvel does four films in 2022 and they put him there instead.
Anything beyond this point is complete conjecture. I think post Avengers in 2023 we will start seeing Fox stuff in full, namely Fantastic Four, Deadpool, and the start of the X-Men. I do think we may start to see more sequels, like ones for Black Panther, Shang-Chi, Eternals, etc.
Maybe more original films, like one on Nova or Young Avengers, both of which have been rumored to be in development.
At least Superman has a couple movies people actually like, LOL!
