How Marvel Should Bring The X-Men Into The MCU

10. Avengers 4 Establishes The Marvel Multiverse

Though the MCU has started to introduce increasingly reality-bending concepts recently with Ant-Man's Quantum Realm and Doctor Strange throwing dimension-hopping and the Eye of Agamotto into the mix, it's still far away from making alternate universes a tangible, pivotal aspect of this franchise.

However, considering that having the X-Men materialise in the MCU out of nowhere would be incredibly jarring, it'd make a lot of sense to have them emerge from another universe as a result of some dimension-melding event.

Given the likelihood that Thanos will cause some catastrophic damage on Earth by the end of Avengers 4 and Doctor Strange may have to use the Eye of Agamotto to set things right, this could easily result in a portal being created between universes, allowing the X-Men to join this world.

Sure, the finer logical details would need to be figured out and it's unlikely much concrete would actually happen in Avengers 4 itself considering it's already wrapped shooting, but it wouldn't be difficult to shoot an extra post-credits tag before release which more blatantly hints at the existence of the X-Men in another universe.

As the MCU Earth is already canonically one of many - with the designation "Earth-199999" - and the next two Avengers films are likely to get very, very weird, introducing a multiverse really just feels like the next big, ambitious step in expanding the franchise's scope.