Microsoft sure loves signing exclusive deals with first-person shooters. In addition to securing first rights to Call of Duty DLC, the company will also get first access to the "Second Assault" DLC for Battlefield 4. It will be available first on Xbox One, and will presumably come to every other platform afterwards.
This isn't the first bit of DLC announced for DICE's new shooter. China Rising is also a pre-order bonus for the game, which ships in October.
Here's the footage they showed from the Xbox conference. According to DICE, the Xbox One version will run at 60 frames per second, unlike your awful, dated current-gen consoles.