The term “Combat Unit” refers to any Unit that is not specifically designated as a Recon Unit, or as a Strategic Unit. They can be sent on all missions except Recon missions.
Each Combat Unit has its own statistics, which influence its performance in battle. Some are better suited to Offense, while others are better suited to Defense. This difference is more noticeable in the most powerful Units.
All Combat Units can be used in all Offensive and Defensive engagements.