I literally just finished the MW3 Campaign, and noticed that the ending is very similar to Black Ops' ending. About 5 minutes before you finish the Campaign in Black Ops, you kill the Antagonist, which is Dragovich. Well in MW3, you also kill the Antagonist, which is Makarov. Now watch these two videos.
Notice how in both endings, you are vulnerable, and about to be shot. The Antagonist says something dramatic, then out of no where, your comrad starts shooting him. Then in both endings, the Antagonist shoots back at your ally (Althought in Black Ops, Dragovich does not kill Hudson), then you take down the antagonist. You're now on top of him, and punching/choking him.
The only real difference in these endings, is how the Antagonist is killed.
In MW3; Price (you) wraps a cord around Makarovs neck, smashes through the glass roof, thus causing Makarov to be hung to death. In Black Ops, Mason (you) grabs Dragovich, they both fall down a ladder, then Mason chokes and drowns Dragovich.
I don't why, but both of these are just oddly similar. Antagonist has Protagonist at gun point, ally comes in and shoots Antagonist. Antagonist shoots back, you grab him, both of you fall some distance, and both Antagonists are choked to death.