Abstract: Programmed cell death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) signaling pathway aids the evasion of tumor immune by producing negative control signals, leading to immune tolerance and promoting progress of tumors. PD-1/PD-L1 targeted immumotherapy, the new therapeutic method of malignant tumors, can restore the immune responses of microenviroment in tumors and mediate proliferation of T lymphocytes that could kill tuomr cells. However, there are differences of immune responses in different patients. To date, there have not been valid clinicopathological biomarkers to identify responders or non-responders. ¹⁸F-FDG PET/CT is a useful, real-time and noninvasive modality for the assessment of tumor glucose metabolism. Positive expression of PD-L1 also has been shown to influent glucose metabolism in microenviroment of tumors. Thus, it is promising that ¹⁸F-FDG PET/CT could be useful to the PD-1/PD-L1 immumotherapy. This review focuses on advances of ¹⁸F-FDG PET/CT in PD-1/PD-L1 targeted immumotherapy of tumors.