https://www.gamespot.com/articles/pokemon-lets-go-pikachu-and-eevees-release-date-pr/1100-6459292/

The Pokemon invasion of your Nintendo Switch has begun. The "free to start" RPG Pokemon Quest is already available, and a new core Pokemon game is heading our way in late 2019. But the lovable critters aren't done with Switch yet. Coming November 16, 2018 are Pokemon Let's Go Pikachu and Pokemon Let's Go Eevee, a pair of games designed for newcomers to the franchise and for players who got their start with the mobile game Pokemon Go.

Developed by Game Freak, the makers of the core Pokemon titles, these Let's Go games share some DNA with Pokemon Go. Instead of battling the monsters to catch them, you'll collect them by tossing Poke Balls at them. You can even transfer Pokemon from Go to Let's Go via Bluetooth. We also know that the first 150 Pokemon as well as their Alolan forms from Sun and Moon would appear in the Let's Go titles.