Of course they are. At this point, any major consumer platform company not working on their own ARM chips is being irresponsible.
Microsoft Corp. is working on in-house processor designs for use in server computers that run the company’s cloud services, adding to an industrywide effort to reduce reliance on Intel Corp.’s chip technology. The world’s largest software maker is using Arm Ltd. designs to produce a processor that will be used in its data centers, according to people familiar with the plans. It’s also exploring using another chip that would power some of its Surface line of personal computers.