Comment
I received a call from this number asking if I was the primary computer user. The lady said she was from "Microsoft Defender" and that there may be some malicious files on my computer. She asked my to turn on my computer, and she would guide me through the steps to clear them. I asked for identification, and she said she had some Windows product license number that only I and Microsoft would have.
Hard to imagine that Windows would call 500,000,000 users individually to help them clean their computers.
I suspect she would have had me look for some legitimate file, say "Aha! you are infected", and then had me download something from the web to clear it.