CD274 and pachyonychia congenita: Recently, immune checkpoint inhibitors, such as anti-programmed death-1 or programmed death-1 ligand-1 (PD-1/PD-L1) antibody, have been developed for various solid carcinomas and have shown broad efficacy [4, 5], but they have a poor effect in the treatment of PC, as seen with PD-1/PD-L1 blockade monotherapy [6, 7].