PDCD1 and cancer: The expression PD-1+CD8+ T cells in cancer patients tended to predict poor overall survival (OS) (HR: 1.379, 95%CI: 1.084-1.753, p= 0.009), and unfavorable disease-free survival(DFS) (HR: 1.468, 95%CI: 0.931-2.316, p=0.099), though it did not reach statistical significance.