Firaxis Games has published the September 2019 game update for Civilization VI, you can check the changelog over here. Besides various bug fixes and enhancements, the update also adds a new "Red Death" game mode. This is basically a battle royale multiplayer mode.
In this new gameplay mode, the world is hit by a radioactive mass and you need to keep your units within an ever-shrinking Safe Zone ring. No new buildings can be constructed in the Red Death mode, the focus is entirely on survival and you win if you have the last remaining Civilian. Red Death matches will typically last about 15 to 50 minutes, depending on the number of players and player skill.