Bing appears to be in for a rebrand that will make Microsoft's role in it much more front-and-center. Some Bing users are currently seeing the Bing logo replaced with one that says "Microsoft Bing" and includes Microsoft's main company logo. It seems this is an A/B test right now, meaning it hasn't rolled out to everyone.
Bing is already widely known as a Microsoft property, but Microsoft's name has never appeared as part of its main branding. This switch would make it much mor evident. The timing is also interesting because it comes months after Microsoft began testing a new, curvier Bing logo.