Reportedly, the expression of PD-L1, which belongs to the B7/CD28 superfamily, is higher in cancer tissues than it is in non-cancerous tissues32 and cancer tissues with high PD-L1 expression correlate with cancer aggressiveness and poor prognosis.33,34 Conversely, some other studies have reported the opposite correlation between prognosis and PD-L1 expression in cancer tissues, including OSCC and lung SCC,35 highlighting the debatable expression significance of PD-L1 in SCC tissues. The gene discussed is CD28; the disease is cancer.