The most I know about Pikachu has been learned from playing Super Smash Bros., but I know the Pokemon character is wildly popular and so a Detective Pikachu movie probably will be, too. Legendary Entertainment struck a deal last summer to bring the live-action film to the screen, and now we know Rob Letterman will be the guy to make it happen.
Letterman will direct the Detective Pikachu movie, which will be a brand new story based on the Great Detective Pikachu video game in Japan. Nicole Perlman (Guardians of the Galaxy) and Alex Hirsch (Gravity Falls) will write the script. The last film Letterman directed was Goosebumps, with the R.L. Stine adaptation proving to be a considerable family-friendly hit. He's hoping to capture an even bigger audience this time, hopefully without the use of Pokeballs.
Detective Pikachu is expected to go into production next year and launch a franchise, of course.