CM Punk defending the WWE Championship against John Cena and the Big Show in a Triple Threat match has been signed for Summerslam on 8/19 in Los Angeles.
Here is the updated card for the event.
WWE Championship – Triple Threat Match
* CM Punk (c) vs. John Cena vs. Big Show.
WWE World Heavyweight Championship
* Sheamus (c) vs. Alberto Del Rio.
* Brock Lesnar vs. Triple H.