https://www.gamespot.com/articles/destiny-2-iron-banner-gear-rewards-whats-new-start/1100-6453830/

The next big event in Destiny 2 is here. Bungie has confirmed that the game's limited-time Iron Banner Crucible event begins today, October 10, and will run for a week. This is the first time Iron Banner has made its appearance in the sequel and while the name is the same, there's actually quite a bit that's changed from the previous game. Below, we've outlined what's different, how to unlock Iron Banner access, and what kind of gear and rewards you can earn by taking part.

To participate in Iron Banner, you need to visit Lord Saladin in the Tower. That task itself requires that you complete the campaign, as the Tower is inaccessible until you've done so. Once you've spoken with Saladin, Iron Banner is entered through its own Crucible playlist, which features Quickplay modes and matchmaking. You can join with a Fireteam or dive in solo.