Indeed, monoclonal antibodies, so-called immune checkpoint inhibitors, which block either PD-1 or PD-L1 (e.g., atezolizumab, durvalumab, nivolumab, or pembrolizumab) are increasingly used to release the “brake” of the immune system and, thus, increase the activity of the immune system against the tumor. The gene discussed is PDCD1; the disease is neoplasm.