From Conflict of Nations Wiki
Combat Recon Vehicle
Lightly armored scout unit, specialized in fast reconnaissance missions. Can identify and uncover stealthy ground units from the start, and they can be upgraded to use air assault.
Armored Fighting Vehicle
Well armored and well armed, AFV's form the backbone of any modern armored fighting force. Not very good at attacking difficult terrain, but can be upgraded to counteract this and airlift.
Amphibious Combat Vehicle
The naval version of the Armored Fighting Vehicle, able to disembark at any coast acting as armored support for naval infantry.
Main Battle Tank
Heavily armored ground unit, used to breach defenses and strike deep into the enemy rear. Especially vulnerable in urban and difficult terrain.
Lightly armored unit dedicated to knocking out enemy vehicles. Very effective in defending urban terrain due to its light build and low profile. Later upgrades will allow this unit to air lift and air assault.