Thanks to @Gavin we were able to identify a way to force the game into fullscreen.
Step 1) Locate your launcher shortcut:
- Should be in C:\Community of Mankind
Step 2) Right click on the shortcut and select properties.
Step 3) Replace “+windowed 1” with “-fullscreen”
Step 4) Click “Apply” and “OK”
Feel free to reply to this thread if you have any difficulties.