In response to the recent speculation that Halo: CE, Halo 2, and Halo 3 will be playable on Steam, which stemmed from a leaked listed of games on the Steam database, Microsoft has confirmed the publisher has no plans to release any of the games on Valve's platform.
Responding to our inquiry, a Microsoft spokesperson gave us the typical, "We currently do not have plans to release any 'Halo' titles on Steam."
With that being said, it's worth noting the spokesperson didn't say PC, just Steam. It's still possible we could see the release of Halo: Combat Evolved, Halo 2, and Halo 3 on PC via Games for Windows LIVE marketplace or the Xbox LIVE Marketplace exclusively for Windows 8.
Let's remember, Halo games weren't the only ones mentioned. The list also mentioned Fez, The Witness, Quantum Conundrum 2, Gunpoint, Owlboy, Lococycle, and Dyad. And there was some validity to the list as Dyad creator Shawn McGrath revealed the PSN shooter would, in fact, be making the leap to Steam.