Although blocking PD-1/PDL-1 can reinvigorate exhausted CD8 T-cells and improve control of cancer, reinvigorated CD8+ T-cells via anti-PD-1 ICB demonstrated minimal regeneration of an effector memory T-cell (Tem) phenotype and return to an exhausted state in the continued presence of high levels of antigen. This evidence concerns the gene PDCD1 and cancer.