https://www.gamespot.com/articles/destiny-2-forsaken-ascendant-challenge-how-and-whe/1100-6461852/

With the latest weekly reset for Destiny 2, Bungie has brought more than just the return of Iron Banner and a new update. If you have access to the Dreaming City, another Ascendant Challenge is now available. Here's where to find the location of its portal and how to complete the challenge once you're inside.