Which Pokémon game introduced the Hisui region and was released in 2022?

Pokémon Legends: Arceus introduced the Hisui region and was released in 2022.

The game launched worldwide for Nintendo Switch on January 28, 2022. Its story takes place in a historical era long before the events of Pokémon Diamond and Pearl. Hisui is the ancient name for the Sinnoh region, and the game shows how that land was explored and eventually became more familiar to later generations.

Players join the Galaxy Expedition Team and help Professor Laventon create one of the region's first Pokédexes. The game changes the usual formula by emphasizing field research, direct overworld encounters, crafting, stealth, and active movement during battles.

Pokémon Legends: Arceus is not the same as Pokémon Brilliant Diamond and Shining Pearl, which are remakes of the earlier Sinnoh games. It is also distinct from Pokémon Scarlet and Violet, whose open-world adventure takes place in the Paldea region.