Looks like COD4 is going to be getting some new game modes on multiplayer. No ETA as yet though, the details so far .
Bare-bones Team Deathmatch
No more excuses. No more blaming Martyrdom or Juggernaut for your lack of skills and kills. Bare-bones Team Deathmatch eliminates the excuses and takes it back to basics with standard Team Deathmatch with no perks, no kill streak rewards. Just you, your skill, and your weapons.
Hardcore HQ
Hardcore HQ requires a lot more than just spamming the HQ position with nades and running in guns blazing. Hardcore HQ encourages more tactical gameplay and communication to win with increased damage, no HUD elements, and friendly fire on.
Multi-bomb Search and Destroy
Multi-bomb Search and Destroy starts every member of the attacking team with a bomb. So everyone has the opportunity to plant if they’re good enough.
Hardcore FFA
Even faster paced Free For Alls, where every bullet counts and playing smart is key for a solid k/d ratio. Standard Free for All rules, with Hardcore mode enabled for extra damage, no HUD, and no health re-gen
Sources:
New Playlists – Status / Process
New Playlist Testing This Weekend