What's the next X-Men movie after Logan?
It sounds like New Mutants, Supernova, and Deadpool 2 are all going to be filming this summer. There are currently 3 "untitled Marvel" movies scheduled from Fox for 2018.
-March 2
-June 29
-November 2
Plus a 4th scheduled for February 14 2019.
Since we heard about those 3 filming this summer, but nothing about X-Force filming that soon, it's not a bad guess to say that X-Force is likely that last one in February 2019.
It's also a decent guess to assume that the June 29 movie will move, since it's one week after Jurassic Park 5 and one week before Ant-Man 2. Don't want to be sandwiched between those two movies.
Sounds like New Mutants and Supernova are much closer to the filming stage than Deadpool 2, so I'll guess that one of those two is next.
Supernova? Where are you getting that title from?
It's a word that's been floating around with regards to the next X-Men movie. Could just be an internal project title, or a shooting title, or even a word on the script title page. It's not yet an official title of the movie, though the movie might possibly be called that.