There are signs that developer Crytek is developing an all new first person shooter franchise, according to the LinkedIn profile of a gameplay programmer.
The resume includes an entry for a “new IP, shooter genre, TBA title for Xbox360, PS3 and PC”. It also mentions another FPS project that he worked on for six months before the title was canceled; it was also a new IP.
Unfortunately, a “new” IP seems to rule out Timesplitters 4, which has been rumored about for ages.