Every commander can have equipment affecting town and troop bonuses

Tap the small head, upper right. The %s of the specific commander and how they and their equipment affect your town will show for you. Each piece of equipment worn by the commander affects the %, and can be changed to make improvements.

For example, the boots on this commander, who is specialized in Gathering, provide him 33% gather and 33% march speed. Whereas the coat below would not benefit a Gathering commander at all. What you choose to outfit your commanders in matters.