When does warhammer 40000 come out on Xbox 360

You mean Dawn of War? Niether one and two are coming out. But you're in luck. Theres a Warhammer 40k game named 'Space Marine' That may come out on both PlayStation 3 and Xbox 360. Its a third person game when you be a space marine with chainsword and bolt pistol and beat the crap out of chaos. Google it. Also Warhammer Mark of Chaos Battle March is on Xbox 360