PDCD1 and cancer: Recently, cancer immunoediting involving immune check point proteins programmed cell death-1 (PD-1/CD279) expressed on tumor infiltrating T-lymphocytes and its ligand (PD-L1/CD274) expressed on tumor cells have come into the clinical focus due the remarkable therapeutic benefits caused by their specific inhibitors in patients with advanced melanoma, renal cell carcinoma and non-small cell lung carcinoma [20–21].