Today, Game Freak have announced two new games for the 3DS: Pokémon Ultra Sun, and Pokémon Ultra Moon. Not a huge amount is known about the games so far, but they will be released worldwide (finally!) on 17th November 2017, exclusively for 3DS.
Pokémon Ultra Sun and Ultra Moon are, as you'd expect, "powered up" versions of Pokémon Sun and Moon, with new additions to the story and features. Rather than being a straight third version or sequel, Ultra Sun and Ultra Moon apparently set out to tell an "alternative version" of the Sun and Moon story. The video reveals that they include two new formes of Solgaleo and Lunala – which appear to be fused with parts of Necrozma, and expanded character customisation options and an altered Alolan Pokédex, with Pokémon not previously found in Alola.