For the first time ever in the Uncharted series history, Uncharted 4 is set to offer single-player DLC that expands the game's storyline.
The previous games in the series offered content only in the way of multiplayer DLC. Naughty Dog, the games' developers, broke this trend with the release of the Left Behind expansion for The Last of Us, and they're set to continue this trend with Uncharted 4.
Details about the single-player DLC are scarce, but the Collector's Edition announcement for Uncharted 4 served as a teaser for things to come.
Given that Uncharted 4: A Thief's End is set to be the final chapter in Nathan Drake's storyline, there's a good chance that the single-player DLC, whatever it may be, will either take place prior to the events of the core game, or put players in the shoes of a completely different character.
We'll find out more when the game is released on March 18, 2016. It's exclusive to the PS4.