In conclusion, our results demonstrate that the PD-L1 expression is markedly different in PPGLs compared to normal adrenal medulla, and the expression may be linked to the genetic background of the tumor, suggesting that targeting the PD-1/PD-L1 pathway in certain PPGL clusters may lead to better outcomes, regardless of the metastatic status of the patient. This evidence concerns the gene PDCD1 and neoplasm.