At least another two films could be dedicated to continuing the run of the main X-Men franchise, as well as a possible sequel to the New Mutants spin-off that’s moving into production now.
Of course, these are release date announcements, no projects, so one has to wonder what properties could possibly fill the 10 untitled slots that Fox has staked a claim in for the next few years.
Right out of the gate, we can assume that at least one Deadpool sequel will be greenlighted in that span, which means that we can definitely count on Deadpool 3 as one of the titles (not to mention X-Force).
There are also still plans to move forward with Gambit, and if they’re getting really desperate for projects, it isn’t totally impossible that they could try something new with the Fantastic Four once the world enters into the third decade of the 21st century.