Microsoft is unlikely to _secretly_ do it, certainly; they would be sued into oblivion, and that’s before the EC gets to them (for GDPR enforcement grinds slow but exceeding fine, and also with exceedingly big fines). US regulators might also take an interest.

Also, modern Microsoft’s _whole thing_, more or less, is “we are your trusted enterprise partner who definitely won’t do bad stuff with the data you put in our cloud services”. They are unlikely to throw that away for a bit of flavour-of-the-month AI boosterism. Note that they’ve recently released a private ChatGPT thing; they can’t credibly acknowledge the problem with one hand and exploit it with the other.