Nintendo, The Pokémon Company and Game Freak revealed during the Nintendo Spotlight: E3 2017 that Game Freak is developing a "core" Pokémon game for the Nintendo Switch. Tsunekazu Ishihara of The Pokémon Company announced the game during the broadcast.
YouTube Clip - Nintendo Spotlight: E3 2017 - Transcript
"I have one more announcement. Game Freak has begun developing a core RPG Pokémon title on Nintendo Switch. It may not release for more than a year but we hope you'll look forward to it all the same." (Tsunekazu Ishihara ,The Pokémon Company)
