COH campaign might not have anything to do with COH 2's development. But the resemblance of some scenes in COH 1 campaign to BoB is just uncanny and I think done on purpose. Similarly, COH 2 soviet campaign reminds me of enemy at the gates at first; and then switches too winter fall/downfall after 1943 in the SP missions.
I'd be inclined to assume it's just writing like most other action video games - totally ripped off/inspired by (feel free to choose whichever, YMMV) the writers' favourite action movies.