Microsoft's proposed acquisition of Activision Blizzard hit a major snag as the UK Competition and Markets Authority has blocked the landmark deal. The antitrust watchdog cited cloud gaming concerns as the reason why the deal didn't get approved.

While the deal has not gone ahead, Microsoft and Activision have both said that they will appeal the decision. Activision Blizzard CEO Bobby Kotick said that the decision is not the final word on the deal and that the company has already started the appeal process.

"Today, the Competition and Markets Authority, a regulatory agency in the UK, decided not to approve our merger with Microsoft," Kotick said. "This isn't the news we wanted – but it is far from the final word on this deal."

He adds, "Alongside Microsoft, we can and will contest this decision, and we've already begun the work to appeal to the UK Competition Appeals Tribunal. We're confident in our case because the facts are on our side: this deal is good for competition."