PDCD1 and cancer: Our data indicate that through combined analysis of PD-1, CTLA-4, CD25, CD28, Foxp3, TGF-β and IL-10 expression and the lymphocyte subpopulations in peripheral blood, we could accurately evaluate the functional status of cellular immunity and PD-1/PD-L1 signaling pathway, which could provide clues for guiding cancer treatment using anti-PD-1 antibodies.