By the time Phase 4 of the Marvel Cinematic Universe comes around (after 2019s Infinity War Part 2), there's a chance (however slim) that Fox will be keen to integrate their X-Men franchise into Marvel Studios game plan. If box office numbers are dwindling and superhero fatigue is growing, itd certainly be a tempting proposition. And what better way to introduce mutants than with Avengers Vs. X-Men, somewhat inspired by the 2012 comic event. Therein, when the evil Phoenix Force was plotting to consume relative-newbie mutant Hope Summers, the Avengers wanted to lock her up whilst the X-Men sought to deal with her themselves. Cue one of the biggest bust-ups in comic book history. Admittedly, even if Marvel and Fox could broker a deal to allow an Avengers Vs. X-Men movie, they would still face the difficulty of meshing together the two franchises continuities. The word mutant has never been uttered in the MCU, but even in the rebooted First Class branch of the X-Men universe lots of people know the term. Theres no way that the universes as they currently exist could fit together. To achieve the crossover, then, Marvel Studios would need to either reboot the X-Men (as they have done with Spider-Man) or introduce the idea of parallel worlds where things are very different. Its unlikely, then, but Avengers Vs. X-Men would be one of the biggest cinematic events of all time if Marvel and Fox could pull it off.
