Since we have highlighted the clinical significance of PD-1+CD8+ T cells, and found PD-1+CD8+ T cells could predict poor OS and inferior chemotherapeutic responsiveness in GC (Figs. 2 and  3), we wondered whether this subgroup of CD8+ T cells was associated with CD8+ T cell dysfunctional phenotype. This evidence concerns the gene PDCD1 and gastric cancer.