Twentieth Century Fox has never shied away from varying the timelines for all of its X-Men movies. The action in the core trilogies and the spin-offs (Deadpool and Logan, of course) has taken place both in the future and in the past. After the release of the first New Mutants teaser trailer, director Josh Boone told IGN that the studio’s going to keep it simple and set the film’s events in the present day.
By setting New Mutants in the present (aligning it with Deadpool), the studio may have found a way to help this movie stand on its own, limiting any connection to the core franchise (Dark Phoenix will be set in the "˜90s).
This did wonders for both Logan and Deadpool.
Boone pointed out that New Mutants is set in the same cinematic universe, so it doesn't mean that there will be no connections at all:
I can't"¦There are some things I can't talk about. I can just say it is connected to and a part of the X-Men universe, and will continue to be a part of the X-Men universe, and will be a part of that as it opens up in the next movies and all that.
We’ll find out later which connections the director was referencing. It’s possible that we could see a surprise appearance by Colossus, who’s Magik’s brother. Of course, New Mutants could also hint at what will happen after the Dark Phoenix events and how (and why) an asylum for young mutants even exists, especially with the alternative presented by Professor X's School for Gifted Youngsters.
New Mutants will be released on April 13, 2018.