Here's some pre-alpha gameplay footage of Warhammer 40k: Dawn of War 3 which was shown at this years E3. The traditional real-time strategy basebuilding is back as well as the introduction of larger-scale walker units - Imperial Knights for the Space Marines, Wraithknights for Eldar and Gorkanauts for Orks.
The game is currently in development by Relic Entertainment and Sega in partnership with Games Workshop, the creators of the Warhammer 40k universe. The third game is a stand-alone title in the Dawn of War series, and the first recent release since Dawn of War back in 2011.
Dawn of War 3 is scheduled to launch sometime in 2017 for PC.