Office was available for Mac for many years. The news here is that Office is now in the Mac App Store, not that big of a news.
Anyhow, worth noting that the Mac versions of Office are no near to the Windows versions. They are thin clients with only a portion of the win capabilities, and those which exists are buggy, to say the least.
If I had a Mac, I would go to G Suite, which gives better capabilities for 99.9% of the users, and if I was on the .1% I would go and buy a PC.
* BTW- Wine 4 was released this week, and they also don't support any of the O365 apps, especially not their 64bit versions.