Cod sells the most on playstation. MS likes money. It's straightforward hehRight. This deal just gives them an even greater revenue stream than them just putting it on their platform from another publisher. They are the publisher/owners so they get a massive growth in the COD revenue stream.
and the amount of microtransactions in COD compared to something like elder scrolls which has none. IMO it would be the absolute worst decision they could make by not keeping COD on playstation.
And if it is mostly from a current deal, i could absolutely see Sony and MS cutting another deal to keep it on PS.