I mean by the numbers COD MW sold 30 million units. That seems to be near historical series highs. So the Cold War one is probably a little over 30 million, but certainly under 40. 32-33 million probably reasonable estimate.
Which is, yes, more. But if you tally single platform (which was my comment) meaning only PlayStation, or only Xbox, or only PC, I doubt any of those are more than Animal Crossing on their own.