Detroit signed Cunningham on Tuesday, Ian Rapoport of NFL Network reports.
Cunningham has played for four different NFL teams in his career, most recently suiting up for seven regular-season games with Denver in 2024. For the first time though, the linebacker was used more frequently on special teams than on defense. He'll probably only fill a depth role for the Lions in 2025, and Cunningham's days of being a lock for 100-plus tackles in a season would seem to be long behind him.