CTLA4 and PD1 are highly expressed by various types of cancers, and their binding to their respective ligands contribute to T cell functional impairment, which fails to elicit the required immunity against minimal residual disease, and thereby play an important role in cancer recurrence.459 The discovery of immune-checkpoint’s role in cancer has changed the paradigm of cancer therapeutics and added immunotherapy to the list of common three cancer pillars including surgery, targeted therapy, radiotherapy, and chemotherapy. This evidence concerns the gene PDCD1 and cancer.