It has had pretty much what Apple are implementing since Windows 10. Dark mode and a custom highlight colour that gets applied across the OS.
Of course like on MacOS developers have to be using the latest UI framework to take advantage of this which unfortunately on Windows developers are a fair bit slower on the uptake than on MacOS.
Then again, I don't expect to see much uptake on the Mac side either considering I can't remember the last time I installed a new app and it was a native AppKit(?) UI and not just an Electron app.