Pokemon Home, the cloud-based Pokemon storage service, will be released in February 2020.
Designed to essentially replace Pokemon Bank, Pokemon Home is compatible with Pokemon Go, Let’s Go Pikachu and Eevee, and Sword and Shield. It can also be linked to Pokemon Bank, which means that it is effectively compatible with all the 3DS Pokemon games, too.
Because of the link to Pokemon Bank, theoretically Pokemon you have collected from as far back as the Sapphire and Ruby generation on Game Boy Advance could be transferred into Pokemon Home.
With all your monsters in Home’s storage, they can then be transferred into Pokemon Sword and Shield, provided the game supports them. And with the new Sword and Shield Expansion Pass adding more older Pokemon to the game, you should be able to take even more of your collection into battle.