The more I think about it these days, I can only wonder what's in store for Matt, Karen and Foggy in Daredevil season 3.
I think right now, there is obviously going to be a LOT of damage control going on for the trio in season 3, given the fallout of season 2 and The Defenders. Foggy probably has it pretty bad. We know from how he dealt with Elena Cardenas' death that he's got a guilt complex, so I would imagine that Foggy blames himself for Matts "death", especially since he IS the one who brought the suit to the precinct. I also imagine him freaking out after Karen's near-death experience during the events of The Punisher, making him desperate to keep his family safe. So, when Matt gets back Foggy is going to be pissed but he will also fight tooth and nail to keep his best friend.
Whatever happens, I want to imagine that Foggy will finally get a chance to talk through things with Matt (in a way that wont end in tears) and will allow them to repair a lot of their friendship, as it gives Foggy a chance to say that he appreciates Daredevil and that the city needs Matt. Depending on what sort of machinations Fisk has in store, Foggy will also be somehow leaving his job at Hogarth Chao & Benowitz, which will send him back to considering reopening Nelson & Murdock
OR he will get a lot more notoriety and might have enough momentum that he starts his district attorney campaign that he had in the comics.
Of course, that's what will probably be happening between Matt and Foggy. That will get a lot of focus, but I imagine that the majority of the focus of season 3 for the protagonist is likely going to go to Matt's relationship with Karen, now that Karen is stepping more and more into Ben Urichs shoes.