Hyperthermia enhances the efficacies of radiotherapy, chemotherapy, immunotherapy, and molecular targeted therapy. In this study, we investigated whether hyperthermia enhanced the efficacy of immune check point inhibitor therapy. The LLC tumor inoculated in mouse was heated and immunostained, which showed increase in PD-L1 staining post-heating. PD-L1 and HLA class I staining increased after heating samples derived from a case of analinvasion of rectalcancer associated with Lynch syndrome.