Mewtwo Strikes Back Evolution, the movie
If anyone has been following the trend in the Pokemon movie series in the last few years, it was to retcon the entirety of the Pokemon anime and the movies, likely up until Pokemon X and Y when they did the style change.
Following the recent release of "Pokemon: Everyone's Story", they ended it with a trailer. There will be a 2019 release under the title of "Pocket Monsters The Movie Mewtwo Strikes Back Evolution". So for those who would like a movie with Mewtwo in it (this would be the 4th), then look forward to summer 2019! (And for those who don't want their 1998 nostalgia trampled over, well, there was your warning!)
Of course, if you ever want to follow updates in the Pokemon World in general, we do highly recommend visiting https://serebii.net/ Serebii.net. They are a fantastic source for information.