Yo-kai Watch 4 is in development for Switch and will launch in Japan in 2018.
Touma Tsukinami, Natsume Amano, Keesuke Amano, and Akinori Arihoshi from the Yo-kai Watch Shadowside anime (pictured) will appear in the game.
According to Level-5 president and CEO Akihiro Hino, “the game content will be super extremely enhanced” and there will be “mechanics that surprise everyone.”
Thanks, Ryokutya2089.
Update 04/11/18 at 3:40 a.m.: Here is the magazine scan announcing Yo-kai Watch 4, via @Japanese3DS.