Pokémon Sword and Shield is limiting the number of Pokémon available in the game to those found in the game’s new Galar region.
Though the Galar region will feature a range of creatures from all Pokémon generations, unlike previous entries, you won’t be able to import every single creature we’ve seen so far.
The assumption was Pokémon Home, the newly announced service that would allow you to upload creatures from Sun and Moon, last year’s Pokémon Let’s Go and also Pokémon Go to store in an online vault, would allow you to transfer everything to the new game – but this is not the case.
Source: Eurogamer Not every Pokémon will be supported in Sword and Shield