PDCD1 and neoplasm: In this study, combined with the LIHC data in the TCGA and the GEO, the immune cell infiltration, ferroptosis genes mutation and copy number change of the TME in LIHC were comprehensively analyzed, and the ferroptosis scoring model was built to quantify the expression level of immune checkpoint inhibitors (e.g., the PD-1, PD-L1 and CTLA4) in LIHC patients, and then the prognosis, tumor microenvironment and application prospect of the immunotherapy in LIHC patients were analyzed and predicted.