Chris Claremont's "Phoenix Saga" is a huge story, so big that it encompasses two multi-issue arcs. The first centers on how Jean Grey assumes the power of the Phoenix and what those initial changes mean, while the second arc takes place later as she becomes corrupted by the power and changes into the Dark Phoenix. Trying to fit it into one movie, like they tried with X-Men: The Last Stand, is a bad idea. So X-Men: Dark Phoenix director Simon Kinberg isn't making that mistake twice, or at least it sounds like he isn't.
Speaking with Collider, Olivia Munn called the film a "two parter", while trying hard not to confirm that she's coming back as Psylocke. Another, less reliable source, Universo X-Men, points to an extra on the film who says they will all be brought back after the first movie is shot to start work on a second chapter.
Makes sense, and would certainly be the right way to go. It also shows 20th Century Fox has a ton of faith in Kinberg to entrust him with directing two movies.
X-Men: Dark Phoenix opens November 2nd 2018, and Fox has an untitled Marvel film set for exactly one year later. Hmmmm...
