Originally Posted by psylockolussus
The difference between MCU and a possible X-Men/Fantastic Four team-up movie is going to be two superhero teams working together rather than superhero individuals coming together and work as The Avengers.
I do think if they ever team up, it should be a 1-shot thing.
Coincidence or not...
Joss Whedon's story on Astonishing X-Men has featured X-Men and Fantastic Four teaming up...(I believe it was on Dangerous' story arc)