What is a Activision account for modern warfare?

Early Access Available to Call of Duty Modern Warfare III Game

Latest Call of Duty game announced! Activision confirms Modern Warfare III

Cant login to Activision account in-game, but can login on web browser. What to do? : r/ModernWarfareII

So Activision allowed my account to be hacked, what's next? : r/ modernwarfare

Call of Duty®: Modern Warfare® II - Urban Veteran: Pro Pack - Call of Duty

It's Anybody's Game in Season 03 of Call of Duty®: Modern Warfare® II and Call of Duty®: Warzone™ 2.0, Launching April 12