In an interview with Comicbook.com, Dark Phoenix writer and director Simon Kinberg described his film as the “natural culmination for this cycle of X-Men movies” rather than an ending forced by Disney’s acquisition of 21st Century Fox.
“From the beginning of conceiving what we were going to do with this film and writing it, which was three plus years ago, so long before there was a Disney merger, I felt like this was the natural culmination for this cycle of X-Men movies,” said Kinberg. “Because it is seeing this family that you’ve come to love and know for how ever many films, and if you count the originals almost 20 years now, you see that family tested in a whole new way. You see that family start to fall apart in a real way for the first time, ultimately come back together.
Source: IGN.com Dark Phoenix Is the 'Natural Culmination' of Fox's X-Men Movies