That being said, a recent tweet has revealed (via Game Rant) concept art that is allegedly for the upcoming Pokemon RPG, and that these will be the starter Pokemon that will be offered to gamers at the start of the game. According to the tweet, “Gen 8 starters for Pokémon. The cave bear is rumored to evolve into Grass/Electric typing, Pony into Fire/Steel, and Coral Pure Water. Thread mysteriously got deleted and images weren’t linked anywhere after reversing which is hype. Could this be Gen 7 leaks all over”.
Of course it’s hard to say if this is the real deal since we’re sure that concept art drawn by fans probably exist, but given that the game is in the works, seeing possible concept art leaked wouldn’t be a stretch either. However it’s still best to take it with a grain of salt for now, especially since save for the announcement, not much else is known about the game.
In terms of a release, last we heard it could potentially be released some time in 2018, and hopefully Nintendo will have some kind of official confirmation soon.