As part of the Activision Blizzard acquisition, Microsoft's aim is to bring Call of Duty to as many platforms as possible. This includes Nintendo's devices, with a 10-year legal agreement already penned.
The only thing Xbox has got to overcome first is the FTC and Sony's attempts to block the deal. The pair are still trying to argue Nintendo is not a direct competitor in the main console market and therefore would not be impacted by this acquisition in the same way as PlayStation.
PlayStation boss Jim Ryan has reiterated this in a pre-recorded deposition on day three of the trial, noting how Nintendo is not a main competitor to Sony. He used Call of Duty as an example of this when asked about its sales on past Nintendo consoles - describing this series' audience as a "very different market" compared to the standard Nintendo audience who enjoys "Mario and Zelda" (thanks, IGN).
Microsoft has already been asked about Call of Duty running on a platform like Switch, but it was a completely different discussion focused on hardware and performance - with Xbox boss Phil Spencer mentioning how he believes it could run "relatively great compared to other Switch games".
Although the FTC is attempting to prove Nintendo is not a direct competitor to Sony, it still seems a bit much when considering the fact Nintendo has been dominating the video game market for years now, with over 125 million Switch units sold as of March 2023 and software sales surpassing the one billion mark in May of this year.