Portal 2 DLC will be released this month, Tuesday 4, to be exact. This DLC will be free on all platforms.
The DLC pack won’t expand Chell’s single-player adventure, it will add “Peer Review,” a whole new cooperative campaign for robot pals P-Body and Atlas.
Also, this DLC will also introduce a “Challenge Mode” for both single-player and co-op play. Players will be able to compete for the best scores and then compare their rankings on Leaderboards.
More details about this notice here: https://www.escapistmagazine.com/news/view/113417-Portal-2-DLC-Emerges-in-October