https://www.polygon.com/2018/1/11/16878088/mario-odyssey-dlc-outfits-trailer-release-date-luigi-balloon-world

Super Mario Odyssey’s first add-on content is coming this February, with a free update that will add Mario’s brother Luigi and two new leaderboard-based online modes to the game, Nintendo announced today in a Nintendo Direct Mini presentation.

Luigi still won’t be a playable character; instead, he’ll be the host of Luigi’s Balloon World, the name for a pair of connected modes in the update. In the Hide It mode, you’ll have 30 seconds to run somewhere in the game and hide away a balloon. In the Find It mode, you’ll get the same amount of time to run around the world and find balloons that other players have hidden. The more balloons you can discover, the higher you’ll move on the Balloon World leaderboards.