https://www.pcgamer.com/everyone-will-be-able-to-play-team-deathmatch-in-pubg-soon/

PlayerUnknown's Battlegrounds developer Bluehole added the team deathmatch-style War Mode to custom games this week, and it plans to roll the mode out to all players as a time-limited event at some point at the future. 

In War Mode, squads jump into a small zone on the map with a pre-determined set of weapons and kill everyone in sight. If you die, you respawn by jumping out of the plane again. The aim is to reach a certain number of points before other squads, and you get points for kills, knockdowns, and revives.