Therefore, the key role of PD-L1 in immune resistance depends on the blockade of its binding toward PD-1, which also plays a crucial role in immune inhibition due to its inhibitory effects on the function of lymphocytes when it binds to PD-L1 [52], so that tumor immune resistance from the cytotoxic cluster of differentiation CD8 T-cells can occur. The gene discussed is PDCD1; the disease is neoplasm.