With regard to biomarkers, although we cannot exclude the possibility of temporal and spatial variation in PD-L1 expression, no apparent association with ICI efficacy was observed in the current study (two responders both had PD-L1-negative disease; Supplementary Table S2), despite a generally positive correlation between PD-L1 expression and response to ICI as well as survival prognosis in other types of cancer (13, 28, 29). This evidence concerns the gene CD274 and cancer.