5. Sony Think They Are
Suggesting the X-Men may be joining the MCU isn't just some crazy fan wish - there's industry rumours that back it up. The main damage from the Sony Hack late last year may have been done, but the email leaks are still revealing new, interesting information. One piece of correspondence,
discussed over on Latino Review, looks at their presumed timeline of upcoming movies from rival studios, including many that haven't been announced yet. One of the furthest away is described as a Fox/Marvel Team Up, due at some point late this decade. As Marvel is only ever referred to as a studio, not the comic company, that implies a movie collaboration. Whether "Team Up" refers to the studios bringing their big properties together (Avengers Vs. X-Men) or simply sharing certain characters (Galactus) is obviously unclear, probably because Sony don't know the specifics, but the most likely development would be a large scale crossover. Although this is just speculation (albeit it at a studio level), Sony have a pretty strong track-record of predicting their opponent's moves - the same timeline mentions The Batman as a November 2018 release,
a rumour that's recently gained traction. At the very least, there must have been some shift in Fox's relationship with Marvel following the Deadpool event for Sony to suspect such a seismic deal.