PlayerUnknown's Battlegrounds has very quietly added a new mode called War on PC. The new mode--which is essentially Team Deathmatch--adds respawns, a mechanic not seen in PUBG's standard battle royale mode.
Players are condensed into a small, static area on Erangel, meaning lives don't last long. The selection of weapons and gear depends on the settings picked by the game's host, so you could spawn with any number of items. War mode is available now but only as a custom game, meaning only PUBG Partners can start and host matches--though anyone can join an already-created session.
The mode was not announced by developer PUBG Corp. or publisher Bluehole, with no mention of it anywhere on social media or on the game's forums. It's therefore unclear how long War will be available for. It could be a timed mode, similar to the game's other new way of playing, Tequila Sunrise, which went live just recently and features close quarters, shotgun-based combat.