Someone jumped the gun.
Looks like someone pulled the trigger early- the final expansion for The Witcher 3: Wild Hunt, and Geralt of Rivia’s final chapter that we will get to play through, Blood and Wine, is apparently available already on Xbox One- at least if you bought the Expansion Pass early.
According to NeoGAF, if you own the Expansion Pass, go to My Games -> The Witcher 3: Wild Hunt -> Menu -> Ready to Install, and then install the add-on. After that, start the game again, and you will see the add-on available in the game to play already. You might as well do it now, too, because it might be taken down again until the official release.
The Witcher 3: Wild Hunt is available on Xbox One, PlayStation 4, and PC. CD Projekt RED are apparently preparing to announce another game related to The Witcher at E3 this year, although it is unclear if the new game will follow Geralt. Stay tuned to GamingBolt for more information and coverage on the game.