Meta-analyses of checkpoint blockade treatment in cancer have clearly shown this to be the case and that, for instance, higher expression levels of PD-L1 by the tumor microenvironment are associated with better response to anti-PD-1 treatment and lower occurrence of adverse events in a variety of cancers [157, 158], although agreement on this topic is not absolute [159, 160]. The gene discussed is PDCD1; the disease is cancer.