https://www.gamespot.com/articles/destiny-2s-new-crucible-mode-breakthrough-now-avai/1100-6462027/

Destiny 2 has kicked off a new competitive multiplayer mode, so you can start trying it out right now. The new Breakthrough mode is available for all players on a special playlist starting today, but owners of Forsaken can play it in private matches as well.

Breakthrough takes place across multiple phases. The first is an area control phase in which both teams clash over a central zone. Capturing it gives one team the control of the Breaker, while the losing team continues to attempt to capture the zone and get the Breaker for themselves. Meanwhile, whichever team is controlling the Breaker uses it to hack the enemy team's Vault. That will start a time limit to win the round, and the best of three wins the match.