https://www.gamespot.com/articles/zelda-breath-of-the-wild-how-to-get-the-xenoblade-/1100-6454859/

Nintendo has rolled out a new update for The Legend of Zelda: Breath of the Wild, and along with adding support for the newly released Champion Amiibo figures, it introduces a special set of gear inspired by Xenoblade Chronicles 2. The new equipment is a set of Salvager armor based on the costume Rex wears in the upcoming open-world RPG, and it's available for free to all players--if you can find it.

As was the case with previous DLC armor, you'll have to complete a sidequest in order to obtain the Salvager armor. The three-part quest appears automatically when you turn the game on after updating, and it's presented as a sort of riddle. You'll need to head to three specific locations and look up at the sky at each one; soon after you do that, you'll see a red shooting star streak toward the earth. Head to where it lands and you'll find a treasure chest containing one piece of the gear.