And incredibly soon! It will be coming out February 3rd in Japan on the 3DS eShop:
It does seem to be an eShop exclusive game at 1,500 Yen (or 1,200 if you buy it early). While that gets me a little down (I would totally pay for a huge detective Pikachu game), I’m just really excited it is happening.
It was brought up ages ago and never really went anywhere, unfortunately. While a lot of people weren’t too big on the game, I love Pokemon and love mysteries and Detective Pikachu was pretty much a perfect combination of that. When I went to England, the very first place I wanted to stop was at 221B Baker Street. I am still upset it was torn down. How dare you, London 
I want to go on Detective adventures with a Mega Audino now. And I am so buying a Detective Pikachu plush if/when one is made.