Considering the possibility of metformin or its analogs in inhibiting PD-L1 and tumor metastasis simultaneously [32, 38], it has inspired us to propose that the combination of mild-PTT and metformin or its analogs will be a potential strategy to overcome the drawbacks of mild-PTT induced immunotherapy, which may increase the immunogenicity of tumors and inhibit tumor metastasis. This evidence concerns the gene CD274 and neoplasm.