With Marvel, it'd have to be an entire new franchise within the current franchise. Like you wouldn't even want a cameo or mention of the rest of MCU because X-Men is just TOO expansive and has too many characters.

With Iron Man, The Hulk, Thor, Black Widow, Hawkeye, Captain America, War Machine, Falcon, Scarlett Witch, Vision, All of Guardians of the Galaxy, Ant Man, Wasp, Winter Soldier, Black Panther, Spider Man, Doctor Strange, Quake, Deathlok, Mister Hyde, Carl Creel, Yo Yo, Gustavo from Narcos, Agent Carter, Daredevil, Jessica Jones, Luke Cage, Iron Fist, The Punisher, Elektra and the potential for Moon Knight, Blade and Ghost Rider pretty soon all being among at least the quick google search of "MCU superheroes" I could find (I guess alone with people who just randomly count as super), I reckon adding in an entire world of X Men would be a bit too much to have going on at one time.

With Marvel, it'd have to be an entire new franchise within the current franchise. Like you wouldn't even want a cameo or mention of the rest of MCU because X-Men is just TOO expansive and has too many characters.

With Iron Man, The Hulk, Thor, Black Widow, Hawkeye, Captain America, War Machine, Falcon, Scarlett Witch, Vision, All of Guardians of the Galaxy, Ant Man, Wasp, Winter Soldier, Black Panther, Spider Man, Doctor Strange, Quake, Deathlok, Mister Hyde, Carl Creel, Yo Yo, Gustavo from Narcos, Agent Carter, Daredevil, Jessica Jones, Luke Cage, Iron Fist, The Punisher, Elektra and the potential for Moon Knight, Blade and Ghost Rider pretty soon all being among at least the quick google search of "MCU superheroes" I could find (I guess alone with people who just randomly count as super), I reckon adding in an entire world of X Men would be a bit too much to have going on at one time.