So this will exist in the Xmen universe but not really tie to other movies, much like Logan and Deadpool did..............also, its supposed to be horror movie.
Explanation of the new mutants universe - https://www.polygon.com/2017/10/13/16464486/what-is-new-mutants-explained
Explanation of the new mutants universe - https://www.polygon.com/2017/10/13/16464486/what-is-new-mutants-explained