I'm working on it: https://twitter.com/stefan_3d/status/1090607219975045120

It should work on any CPU with SSE4.2 support, which includes all modern AMD CPUs.

Intel's graphics libraries are well crafted and pleasant to integrate. In fact, Embree is currently being integrated into Blender's Cycles as an alternative ray engine.

I'd guess we'll see an effort at integrating the Intel denoiser fairly soon as a plugin at least.

Someone recently released a Blender plugin using the NVIDIA Optix denoiser, which I think couldn't be directly integrated due to licensing issues:

https://remingtongraphics.net/tools/d-noise/

Slightly related, came across this addon[0] that allows you to use NVIDIA OptiX Denoiser directly from Blender.

[0] https://github.com/troopy28/OptiX-Denoiser-for-Blender