The CMA wants to see if rivals can easily connect their own AI tools with Microsoft's software or if the playing field is tilted.
They're also taking another look at how Microsoft handles cloud licensing, a hot topic since both Microsoft and Amazon faced scrutiny for dominating the cloud market.
CMA chief Sarah Cardell says keeping this market open and fair really matters for UK businesses.
Microsoft says it's ready to cooperate as the investigation continues through February 2027.