In the combined cohorts, the p16-negative immunostaining was associated with higher response rate (RR, p=0.02) but did not impact survival while higher PD-L1 combined positive score was associated with higher RR (p=0.03) and longer OS (log-rank p=0.04). In the p16-positive patients, median (log-rank p=0.05)....The combination of cetuximab and nivolumab is effective in patients with both previously treated and untreated R/M HNSCC and warrants further evaluation.