X-Men Could Appear In The MCU:
We have all wondered and waited for X-Men to get included in the Marvel Cinematic Universe, but it never really happened. For almost two dozen movies and a handful of TV shows, the characters have operated in a world in which mutants have not once even been mentioned. The reason for this was the longstanding, uneasy relationship between Marvel and 20th Century Fox. For years, Fox had the live-action movie rights to the X-Men, Fantastic Four, and any related character. This scene where the rights are with Fox, forbid Marvel to make any mention of the mutants, with even the word “mutant” being verboten. In fact, back in 2001, Fox sued Marvel over its planned Mutant X television series, even though the series was to be based on entirely new characters with a completely different origin story than the X-Men and already-existing mutants of the world.