Phil Spencer will retire after 38 years at Microsoft; Asha Sharma, the president of product in Microsoft's Core AI business, will become the CEO of gaming (Jordan Novet/CNBC)

Jordan Novet / CNBC: Phil Spencer will retire after 38 years at Microsoft; Asha Sharma, the president of product in Microsoft's Core AI business, will become the CEO of gaming   —  Microsoft's head of gaming, Phil Spencer, is leaving the software maker following a 38-year tenure, as the company faces increased challenges in its Xbox business.