Escaping enslaved individuals often provided valuable information about Confederate positions and troop movements, providing the North with significant strategic advantages. They were also sometimes employed in noncombat roles such as spies and scouts, or acted as guides and laborers.
It's important to recognize the agency and contributions of enslaved people during the war, and remember that their assistance to the North wasn't always motivated by a loyalty to the Union, but also by a desire for personal freedom and the abolition of slavery.