Direct sequel for Black Ops possible

Treyarch has not ruled the possibility out
While Treyarch’s community manager claims, “Your guess is as good as mine,” when asked where the developer might go with the future of the franchise, it does seem that with the success of Black Ops it might be the right decision for the developer and Activision to continue to build the Black Ops brand with another title in the series.
Continuing Black Ops would actually give Activision another brand to work with in addition to the Modern Warfare brand. The Modern Warfare brand is expected to see the announcement of the third installment in the series later this month.
Treyarch is very pleased with the success of Black Ops and it, along with the first map pack release title, First Strike, has exceeded its expectations. The title has become the best selling video game of all time, with a staggering 13.7 million units sold in the United States alone. It is expected that a second map pack release is in development and will drop before the release of Modern Warfare 3, which is expected to arrive in November.