Pokemon: The First Movie - Mewtwo Strikes Back came out quite some time ago, but it's getting a remake in Pokemon the Movie: Mewtwo Strikes Back EVOLUTION. It was a hugely important moment in Pokemon history, so it only seems right to give that original a remake. Turns out that's not the only film keen on the first movie though, as Detective Pikachu ties into Mewtwo Strikes Back as well.
In an interview with Comicbook.com, Detective Pikachu co-writer Benji Samit explained how his film and Mewtwo Strikes Back sync up.
"Mewtwo has always been a part of this because he's in the game, and we knew he was gonna play a big role. In writing it, it became this thing of: we have to be clear that there's only one Mewtwo.
When we're doing this movie that's set in such a different world of Pokemon, we didn't want it to feel like a disconnected universe that is just an alternate history that uses the same creatures. We wanted to be very clear that this movie is part of the greater Pokemon universe, and so if Mewtwo's in it, he's probably gonna be the same Mewtwo."