No, not really.
Judging by people's reactions though, you might think this is what happened- it didn't.
What has happened is that Bungie (the Halo company that doesn't own Halo- still an Xbox exclusive) has begun production on it's first non-Halo game in a really long time, (was Oni the last one?) and has given the much maligned super-publisher Activision the exclusive global, multi-platform, multi-device (!) publishing rights to that title.
So, in a nutshell, we'll be seeing an Activision logo in place of the Microsoft Game Studios logo in the first few screens after starting up the new game on our 360's, PS3's... iPad's? That 'device' part has to make you wonder...
Also, I should note that (even though I didn't want to get into it on this blog) Call of Duty developer Infinity Ward has just very messily broken up (basically) with Activision. So you might think of this move as Activision kind of swapping out IW and slappin' in a fresh clip full of Bungie. At least, on a trial basis.
Full story @ Edge