https://www.polygon.com/2018/12/4/18124521/pokemon-go-trainer-battles-pvp-details

Pokémon Go will introduce PvP later this month, Niantic announced. Trainer battles, as teased late last week, bring the game closer than ever to a multiplayer experience, although there are marked changes from the traditional Pokémon battles many players are familiar with.

Trainer battles allow for one-on-one matches against either another player or a computer-controlled opponent, with each side bringing a team of three Pokémon (called their battle party) into the arena with them. A timer is set for four minutes; whoever knocks out the other player first wins. If both players still have Pokémon remaining by the time the clock runs out, the winner will be the trainer whose Pokémon have the most health remaining. No matter who wins, each person will receive prizes, like the elusive Sinnoh Stones.