https://www.polygon.com/2018/8/31/17798842/destiny-2-forsaken-gambit-mode-pvp-bungie-interview

Destiny 2: Forsaken’s new Gambit mode was one of the most intriguing additions teased in the expansion’s announcement in June. It sets out to marry Destiny’s two core pillars — PvE and PvP — in one mode. But Gambit didn’t start out that way.

Gambit is Destiny’s first ever PvEvP game mode. Two teams of four players each drop into separate arenas, battling various enemies within those spaces. When the enemies are killed, they drop items called motes; players gather and deposit them in a giant, cylindrical bank in the middle of the arena. The first team to bank 75 motes spawns a boss, and the first team to take down their boss wins the round; matches play out in a best-of-three format.