Psalm 7's title says David sang it concerning the words of whom?

Answer: Cush, a Benjamite

Psalm 7 is "a Shiggaion of David, which he sang to the LORD concerning the words of Cush, a Benjamite."

“A Shiggaion of David, which he sang to the LORD concerning the words of Cush, a Benjamite. O LORD my God, I take refuge in You; save me and deliver me from all my pursuers,”— Psalm 7:1 (BSB)