20th Century Fox has set aside six dates for untitled Marvel/X-Men films, according to a tweet from Exhibitor Relations.
The dates are June 7, 2019, November 22, 2019, March 13, 2020, June 26, 2020, October 2, 2020, and March 5, 2021.
These dates have yet to be confirmed by Fox, but should the report be corroborated, that would mean Fox's current schedule extends even further than Marvel, Warner Bros. or Sony's for their cinematic universes. November 6, 2020 is the latest date claimed (by Marvel Stuios) for an unnamed film.
Fox's next X-Men film, X-Men: Dark Phoenix, is currently in production for a November 2, 2018 theatrical release.