The Renegade Pokémon returns to five-star Pokémon GO Raid Battles from September 23, 2019, at 1 p.m. PDT, to October 17, 2019, at 1 p.m. PDT. The Legendary Pokémon is a capable combatant because of its powerful Ghost-type attacks, but even if you're more interested in collecting than battling, there's reason to get excited. Lucky Trainers may encounter Shiny Giratina for the first time during its return to Raid Battles, so make sure to challenge the Legendary Pokémon as often as you can.
The same tactics you used to face Giratina in previous encounters will work again here. It's weak against Ice-, Ghost-, Dragon-, Dark-, and Fairy-type attacks, so use your most powerful attacks of those types to earn as many Premier Balls as you can. Good luck, Trainers!