Microsoft Game Studios released new gameplay footage of Gears of War 4 running at 4K and stated the following below.

Starting today on the gamescom show floor, we’re excited to give fans their first opportunity to play Gears of War 4 on Windows 10 PC. Gears of War 4 is powered by a completely new rendering engine, with the Windows 10 version supporting comprehensive video settings, increased texture resolutions, dynamic resolution support up to 4K and more.
In this short gameplay demo through the “Rescue” chapter of Gears of War 4, our heroes JD, Kait and Del are chasing a large unknown enemy through an old COG fort. Along the way, they encounter two fierce Swarm enemies – Drones and Pouncers – for the first time, and have to battle their way through them before it’s too late. You can watch the video above or view it on YouTube.
In addition, we’ve also announced the minimum, recommended and ideal specs for playing Gears of War 4 on Windows 10 PC

Spec’s for what you need to run the game on PC/Window’s 10 also came out.

Source: NeoGaf VIA Xbox Press Release