Interestingly, PIK3CA alteration was negatively correlated with OS (HR 1.99, P = 0.027), while TERT promoter mutation showed a positive correlation with OS (HR 0.44, P = 0.05)....Our single institution data with anti-PD-1 ICB Tx in R/M HNSCC is consistent with registration study results. The correlation between PIK3CA and TERT promoter gene alterations and ICB outcome warrants further investigation.