Unity of Command is described as 'innovative and refreshing operational-level wargame that covers the entire 1942/43 Stalingrad Campaign on the Eastern Front' and is a Turn Based Game in the Games category. There are four games similar to Unity of Command for a variety of platforms, including Windows, iPad, Mac, Linux and Steam. The best alternative is Panzer Corps. It's not free, so if you're looking for a free alternative, you could try Lgeneral or Panzer Marshal.
Panzer Corps Wehrmacht is the award-winning turn-based strategy game that the press has called “…nothing short of brilliant” and “the spiritual successor to the Panzer General series”, with high rankings and praises around the world. Represent entire series of Panzer Corps games including Panzer Corps, Panzer Corps 2.