There won't be anymore Call of Duty: Modern Warfare 3 DLC released, but Activision has two new multiplayer modes for fans to enjoy in the game's latest playlist update (via EGM). 3v3 Hardcore Face-Off and Money in the Denk are the two newcomers, and you should be able to find them now among the list of game modes.
The 3v3 Hardcore Face-Off is pretty self-explanatory, dropping six players into the smaller, Face-Off-exclusive maps using Hardcore rules, which dials up bullet damage, eliminates your minimap, and turns on friendly fire. Money in the Denk is a variation on the game's Sabotage mode, created, as the title suggests, by Machinima's Denk. You can see how it works in the video up top.