Destiny's big September update could be titled The Taken King, if a trademark which popped up a few days ago is accurate.
Earlier this year, an expansion schedule leaked, and it's thought The Taken King is being developed under the codename Comet. Until anything is confirmed, though, take it as a possibility instead of a confirmation for the time being.
The next expansion for the game is slated to release on May 19, and more on House fo Wolves will be shown later today via a livestream from Bungie. The focus will be on Prison of Elders.