GO Park enables you to transfer Pokémon from Pokémon GO to Pokémon Let’s Go Pikachu and Let’s Go Eevee

A recently-revealed new feature, GO Park is enabled as a player progresses further in the game and will help players befriend Pokémon from Pokémon GO in Pokémon Let’s Go Pikachu or Let’s Go Eevee This feature allows for Kanto region Pokémon from Pokémon GO to be transferred to Pokémon Let’s Go Pikachu and Let’s Go Eevee. These Pokémon will then need to be captured with a Poké Ball again. The player can interact with them in a whole new way in Pokémon Let’s Go Pikachu and Let’s Go Eevee.

Source: @Pokemon