We have no idea when an X-Force movie would land in theaters, but it would probably be sometime after Deadpool 2.
Deadpool made nearly $780 million worldwide and is now the highest grossing movie in the X-Men franchise.
That seems very unlikely, as Fox seems to have big plans for the future of the X-Men franchise.
Fox has definitely made some mistakes along the way, and up until X-Men: Days of Future Past, the X-Men franchise had never been one to pull in the massive money that one has come to expect from superhero movies.