Next-Gen are reporting that, according to an ex-Activision employee, Call of Duty 4 developers Infinity Ward have signed a deal with Activision which ensures that every Call of Duty game will herein by developed by the series' creators. As it stands, development duties are split between Infinity Ward (CoD1, 2 & 4) and Treyarch (CoD3 & 5), but the new deal will mean that only Infinity Ward will be allowed to develop games which carry the Call of Duty name. The agreement will kick in once Treyarch have finished Call of Duty 5, and interestingly, has affected not only the core CoD series, but a rumoured spin-off franchise as well.
The same ex-Activision staffer also claims that Activision Underground, an Acti studio that was closed last week, was shut down due to the agreement. See, Underground were apparently working on a third-person, action-adventure Call of Duty title, that was intended to be the first of an annual series of games, which would have given Activision an excuse to churn out multiple CoD releases in a single year. However, since the rumoured deal now grants IW exclusivity over the IP, Activision shut the spin-off down, and the studio with it.
Source: Infinity Ward Reclaims Call of Duty [Next-Gen]