Gears of War 4 will support Split-screen Co-op and 21:9 resolutions on PC from launch, but will lack HDR support due to HDR compatible hardware and the lack of HDR monitors.
Gears 4 has HDR on Xbox One S. It does not support it on PC. PC just started incorporating HDR support on cards recently, and many monitors don’t have the functionality.
The PC version does support full 4K, Ultrawide, etc.
At launch, HDR support will be exclusive to users of the Xbox One S, provided that they own an HDR ready display.
I agree some PC users connect into HDR TVs but as of now we do not have support for it. We may incorporate it in a later update though if demand grows.
HDR support may come to the PC version of the game after launch, although at this time there are very few HDR TVs and monitors available on the market, which means even the game supports it, most gamers will not be able to play the game with HDR colour anyway.
Gears of War 4 will release on October 11th on both Windows 10 PC and Xbox One. If you want to know about the system requirements, then check our post here.