To investigate the mRNA and protein expression of Sema4D, Plexin-B1and PD-L1 in sensitive cell line and insensitive cell line of melanoma, mRNA and protein expression of Sema4D, Plexin-B1 and PD-L1 of B16-10 and B16-F10R were detected. The gene discussed is CD274; the disease is melanoma.