Programmed cell death ligand-1 (PD-L1) on the surface of antigen presenting cells and tumor cells interacts with programmed cell death protein-1 (PD-1) receptor on T cells to inhibit T-cell activity by eliciting immune checkpoint responses [1, 2] Tumor cells escape immune surveillance by upregulating the expression of PD-L1 in response to IFN-γ secreted by activated T cells [3, 4]. The gene discussed is PDCD1; the disease is neoplasm.