Activision Blizzard game titles like Call of Duty were rumoured to be developed exclusively for Xbox consoles, but Microsoft president and vice-chair Brad Smith addressed them. In his post on new app store principles, Smith reaffirmed his belief that Microsoft's plans go beyond simply making CoD and other popular Activision Blizzard games available on PlayStation. Smith said that in line with the existing agreements . Microsoft made a commitment to Sony that the games would continue to be available for PlayStation "well beyond" the agreement.

Microsoft is "interested" in taking similar steps to ensure that Activision Blizzard games are available on Nintendo platforms like the Switch, Smith added in his post.
The post specifically mentions that "popular" titles will continue to be supported on multiple platforms. With Microsoft now owning Activision Blizzard, it is likely that Microsoft will eventually release at least one Activision Blizzard exclusive to the Xbox and/or PC. However, the wording of today's post suggests that franchises like Call of Duty, Overwatch, Diablo, and possibly others could remain multi-platform for some time to come.
Smith details the changes to the Microsoft app store that the company is planning to implement soon on the Xbox Store. By releasing games through the Xbox store, Microsoft-owned studios would avoid additional hurdles faced by developers not affiliated with Microsoft.
Smith continues to outline changes to the Microsoft app store that the company plans to implement soon on the Xbox store. Microsoft-owned studios would otherwise avoid additional hurdles that developers not affiliated with Microsoft can overcome when they turn to the Xbox store to release their games.
Microsoft's Open App Store plans, however, include one notable exception - the Xbox Store. Microsoft claims that gaming consoles are sold to gamers at a loss as a means to develop a robust game development ecosystem. In the dedicated console store, the company referred to "closing the gap" between reality and its stated principles without giving a clear timeline on when this will happen. The principles outlined will not apply "immediately and wholesale" on Xbox.