Pokémon Sleep is adding Latios on June 8 as part of the upcoming “Latios and the Soul Dew” event, which will run through June 15. The Legendary Pokémon’s debut will give players a new research target during the limited-time event, likely alongside themed missions, bonuses and special encounters. Latios joins the growing lineup of Legendary Pokémon gradually being introduced into Pokémon Sleep through seasonal content updates. The event also continues the game’s strategy of pairing major Pokémon debuts with dedicated story themes and collectible rewards to keep players engaged between larger updates.
Source: Official Pokémon Sleep news and PokemonSleep.net