A Detective Pikachu game is in development for Switch, Nintendo announced at the Pokemon 2019 Press Conference.
Here is the announcement, via The Pokemon Company:
The release of the Pokemon Detective Pikachu movie has left fans wanting more of the famous Pokemon sleuth. The Pokemon Company announced today that Creatures Inc. has plans to create a new entry in the Detective Pikachu video game series, this time for Nintendo Switch. The original Detective Pikachu game for the Nintendo 3DS ended on a cliffhanger and this upcoming game will be a conclusion to that story.