Details are sparse but the latest iteration in the spinoff series, Pokémon Rumble, is called Pokémon Rumble World. To date, the Pokémon Rumble series has had 3 iterations each on separate consoles.
Unless Nintendo decides to release this game on mobile, Pokémon Rumble World would break this trend. As Pokémon Rumble is a spinoff series, this could be the perfect opportunity to get smartphone users into Pokémon without giving them a main Pokémon game.
This rumor could very well be faked as the rating date coincides with Nintendo’s press conference.