The Legendary Pokémon Ho-Oh has returned to Pokémon GO. The iconic Rainbow Pokémon and its rare Shiny form are now available in Raid Battles until August 27, to coincide with the ongoing Johto Week festival. The official announcement from the development team at Niantic is as follows:
Attention, Trainers! For a limited time until August 27, the Legendary Pokémon Ho-Oh is returning to Raid Battles. This will be your chance to end Johto Week with a surprise, as you just might encounter its Shiny form!