Destiny's second expansion, titled House of Wolves, will not have a new Raid and will instead offer a three-player cooperative multiplayer arena mode.
According the Bungie blog, the developer didn’t make the decision to omit a new Raid from the upcoming expansion lightly but placated it is creating a new Raid for a release later this year. This gives weight to Activisionexecutive Eric Hirshberg’s claims the biggest content release yet is coming after House of Wolves.
The “new cooperative end game activity” packaged with House of Wolves is a three-player cooperative multiplayer arena called The Prison of Elders that will focus on “variety, replayability, and skill.” Bungie plans to show off live gameplay of Prison of Elders on Wednesday, May 6.
Prior to that on Wednesday, April 22, the developer will give a walking tour of the The Reef, with an overview about gear upgrade paths. Then live gameplay of Trials of Osiris and its collection of end game gear will be revealed on Wednesday, April 29.
Activision announced a Tuesday, May 19 release date for the new content earlier today. For more on Destiny, be sure to check out IGN's wiki for the shooter as well as our review of the first expansion, The Dark Below. 
http://www.ign.com/articles/2015/04/13/destinys-house-of-wolves-expansion-will-have-no-new-raid
