The next Pokémon GO GO Pass and GO Pass Deluxe will be available beginning July 7, giving Trainers new Pass Tasks to complete for rewards throughout the event. Players who progress through the standard GO Pass can earn encounters with Ho-Oh or, with luck, Shiny Ho-Oh, along with a Gimmighoul holding a 10th anniversary coin and other in-game rewards. Trainers who upgrade to the GO Pass Deluxe can unlock additional premium rewards as they advance through the same Pass Tasks. Niantic says the new GO Pass offers more opportunities to collect exclusive rewards during the limited-time event.
Source: Official Pokémon GO blog