The Pokémon Company just held a presentation in Japan, and they made several major announcements. After unveiling Pokémon Quest and the long-rumored Pokémon Let's Go, Pikachu! and Eevee!, they teased something even more exciting. The Let's Go! games are something of a halfway point between a typical Pokémon game and Niantic's Pokémon GO. If you were hoping for something a little more traditional, there's good news!
These two "casual" games were followed by the promise of something more substantial. The Pokémon Company has confirmed that an " all-new core series Pokémon RPG" is in development and will release in the second half of 2018. They did not specify a platform, although Nintendo Switch would be a fairly safe bet. That said, it's entirely possible they could release it for mobile as well.
This could be an eighth generation of Pokémon games, or perhaps another remake. There are plenty of fans clamoring for another visit to the Sinnoh region, but that might be overkill considering the Let's Go! games are revisiting Kanto. The use of the phrase "all-new" also lends itself better to an eight generation.