In patients with advanced lung cancer, next-generation sequencing (NGS) has determined STK11 and KEAP1 mutations to be relatively frequent drivers of treatment non-response to PD-1 inhibition despite a high TMB; in the future, NGS methods may be helpful in uncovering similar predictors of PD-1 susceptibility in R/M HNSCC [66]. This evidence concerns the gene PDCD1 and head and neck squamous cell carcinoma.