From Cold War Crisis Wiki

Co-Op is a mode where players start with pre-built bases and must cooperate to win the match. Each player can only build select units and upgrades, whereas working together is required to have a balanced army. The maps are (usually) 2 VS 2 players where each player is assigned a specific role.

Maps

So far only the map Joint Ops has been availible officially, but there will surely be other fan-made maps.

Joint Ops

This map separates the players with a large body of water and the only path for ground forces is to the north of the map or the bridge in the center. There are plenty of flags and fuel depots availible.

Objectives

The objective is...well to annihilate your enemy. Working together is essential to success. Capturing depots and flags early in the game will help to raise funds for attacks.