CD274 and head and neck squamous cell carcinoma: Higher tumor mutational burden (TMB) was associated with ICI therapy response in GC (p = 1.55e-6), exhibiting a similar pattern in HNSCC (p = 0.14), the only two cancer types with such data available (Supplementary Data 19).To determine the relationship between virus positivity and other prognostic markers of ICI therapy response, we compared the expression of PD-L1 [CD274] in TCGA’s studies of GC105, HCC118, and HNSCC119.