According to Empire, Ken Watanabe will join Ryan Reynolds, Justice Smith and Kathryn Newton in the upcoming Detective Pikachu, where Pikachu is a detective who can speak, and is out on a mission to find the missing father of Justice Smith's character.
Ken Watanabe (Godzilla, Inception) will play a character specifically created for him called Detective Yoshida. It is possible he will be the antagonist of the movie, a corrupt cop who tries to stop Pikachu from finding the missing man. At this point in time, however, very little is known about the plot of the movie.
The film is being directed by Rob Letterman (Goosebumps) and is written by Nicole Perlman (Guardians of the Galaxy) and Alex Hirsch (Gravity Falls), and will mostly start shooting this month. It has been slated for release in the first half of 2019. Pika-pika!