Is the Mewtwo in Detective Pikachu a Mewtwo we know?
Spoilers ahead.

Haven't watched the movies or anime, but I play the games, and according to this article, this Mewtwo


   is the same Mewtwo that appeared in the original Pokemon anime and movie two decades ago. The movie referred to here is Pokémon: The First Movie. This was the Mewtwo from the Kanto region which escaped Team Rocket.