MS already has a Windows device running on ARM that's capable of running x86 code through translation/emulation (unlike the Surface RT from a few years back) as well as native ARM code. Surface Pro X (
https://www.microsoft.com/en-us/p/surface-pro-x/8vdnrp2m6hhc?activetab=overview ). It can run all 32-bit x86 Windows applications, but not all 64-bit Windows applications will run. I haven't kept up on this so things may have improved since last I looked.
Windows on ARM has been a long going initiative for them. The biggest hurdles have been getting x86 code to run in it at acceptable speeds.
It'll be interesting to see how Apple handles compatibility with existing Mac applications or if they'll just require native ARM version for the ARM based Macs and not support x86 based Mac applications on the ARM based Macs.
Regards,
SB