As you can see, this version of Close Combat is "playing" at the Russian front. More specific, the invasion of Russia by the German forces.
In my opinion, I think this version is the most popular in the CC community (Although I prefer another version). Probably because there are a lot of mods and maps out there on the www. for this version. Also this version works with a point system which makes it usefull to play tournaments for points on all the maps that exist.
There are a lot of mods out there for this version. Have a look at the CC3 mods page if you want to know more.
At the links section, you will find links to Mods etc.