https://www.gamespot.com/articles/heres-why-there-are-so-many-pokemon-sequels-these-/1100-6454236/

Elsewhere in our interview, Game Freak shared why Pokemon Ultra Sun and Moon aren't coming to Nintendo Switch and explained how the upcoming games are helping the development of Pokemon for Switch. The 3DS games launch on November 17, featuring an "alternate" story and some new Pokemon. If you're still playing last year's games, however, you can check out all the free Pokemon and items you can get in Pokemon Sun and Moon right now.