In HNSCC, TMB was investigated in a retrospective study of 126 patients treated with anti-PD-1/anti-PD-L1 therapy, showing higher TMB in responders compared to nonresponders (median OS 17.7 vs. 7.1 months, p < 0.01) [75]; TMB was higher in smokers. This evidence concerns the gene CD274 and head and neck squamous cell carcinoma.