The expression of PD-L1 was significantly and inversely correlated with that of Siglec-15 (R =  − 0.311, P = 0.000, Table 2), and 36, 33, 92, and 21 NPC patients presented with PD-L1+/Siglec-15+, PD-L1−/Siglec-15 + , PD-L1+/Siglec-15−, and PD-L1−/Siglec-15− tumors, respectively (Table 2). The gene discussed is CD274; the disease is nasopharyngeal carcinoma.