Long the domain of workarounds and Assimilate Scratch, you can now create ProRes files on a windows machine with Premiere, Media Encoder, and After Effects.
You've long been able to read ProRes files on a Windows machine, installing the codecs and opening them with Quicktime Player, Resolve, Premiere, even Media Composer, and having them play just fine. The issue was always with writing the files. You got to the end of the session and your client wanted you to make a ProRes444 master, and you couldn't do it. You were stuck with DNxHR (which is a wonderful codec, but not as "famous") or CineForm. Clients wanted ProRes. It was a hurdle.
Of course, that hurdle kept people buying Macs. I know of at least one posthouse that kept around a Mac after going to Windows for most of their edit stations so that they could open the project there for writing their final exports. Many theorized it would always be this way, that Apple would never really put the effort into supporting software vendors of PC applications for writing ProRes.
It was, of course, technically possible. Assimilate (the makers of Scratch) were the only ones to do it with any form of stability, but its software is pricey. There were a variety of other applications that would pop up over the years (only to disappear a few months later) that tried to reverse-engineer the ProRes codec so that it could write it on a PC, but it never quite successfully worked. It was buggy and unpredictable, which isn't something professionals want for making deliveries.
Thus, many would occasionally rent a Scratch license for a month when they needed to do ProRes dailies for a client.
That era is now over as Apple and Adobe have worked together to bring ProRes authoring to the Adobe Suite. This is major.
In After Effects, Premiere, and Media Encoder, you can write to ProRes 4444 and 422. Adobe doesn't quite have an amazing dailies workflow, but you could, if you wanted to, do dailies with Media Encoder straight to ProRes. More useful than that, you can move a project back and forth between Mac and PC, working with ProRes files, then finish on either machine.
This is probably a great time to review our wonderful ProRes street names grid. Right now, no one can write to ProRes Raw, and only Final Cut X can even read ProRes Raw, but we can now work freely, on a PC or Mac, with the other common flavors.
It will be interesting to see how quickly Resolve and Media Composer are able to catch up. A PC Resolve Station with a ton of NVIDIA cards writing ProRes dailies would be killer.
The Adobe Blog has more info.