Bungie's final Halo universe game, Halo: Reach, is a prequel to the original game and will not feature Master Chief, that we know of at this time. The ending of Halo 3 left things quite open for more Master Chief action.
Microsoft-owned 343 Industries will pick up the reins on the franchise and handle all things Halo-universe, which is not just limited to games. It is unclear if Master Chief will be returning in a 343 developed game or in some other form of media.
If it is a game, this makes Halo 4 a possibility with the story picking up from the (warning: spoilers!) ending of Halo 3.