Activision gets cozy with companies when it comes to games. There have been Call of Duty exclusivity arrangements for a while now. Call of Duty: Black Ops III was something of a cut-off point, with games before it having DLC as timed exclusives on Microsoft consoles before that and games after it being BFFs with Sony systems. Which isn’t exactly great, but people grudgingly accept it. But with Call of Duty: Black Ops 4, Activision may have crossed a line and gone a little too far with its timed promotions. It all has to do with League Play.
Source: N4G PC Has Call of Duty Become a Little TOO Exclusive