https://www.gamespot.com/articles/destiny-2-xur-location-guide-wheres-xur-and-what-e/1100-6454846/

Like that one song that Spotify keeps playing even though you're in shuffle mode, Xur is back. This time Destiny 2's best Resident Evil 4 Merchant cosplayer has landed on Nessus, and to get to him all you've got to do is fast travel to Watcher's Grave.

Once you've landed, bring up the map and pop a waypoint on him. If you've been playing Destiny 2 since launch, you'll no doubt be familiar with this spot, as it's a frequent haunt for our boy Xur. If you haven't, it's as easy as hopping on your Sparrow when you land, boosting straight forward, and then doing some light platforming up the tree to find him hanging out on a branch.