AbstractBackgroundClear cell renal cell carcinoma (ccRCC) is one of the most lethal malignancies in the urinary system and the existing immunotherapy has not achieved satisfactory outcomes. Therefore, this study aims at establishing a novel gene signature for immune infiltration and clinical outcome (overall survival and immunotherapy responsiveness) in ccRCC patients.MethodsBased on RNA sequencing data and clinical information in The Cancer Genome Atlas (TCGA) database, we calculated proportions of immune cells in 611 samples using an online tool CIBERSORTx. Multivariate survival analysis was conducted to determine crucial survival-associated immune cells and immune-infiltration-related genes (IIRGs). Next, the clinical specimens and common renal cancer cell lines were applied to confirm IIRGs expression at protein and RNA levels. Finally, functional enrichment analyses and siRNA technology targeted toRUFY4were implemented to verify its function of predicting immunotherapy response.ResultsFollicular helper T cells (TFHs) and Regulatory T cells (Tregs) were highly infiltrated in the tumor microenvironment (TME) and their relative proportions were independent prognostic factors for patients. Among IIRGs of TFHs and TREGs,RUFY4was found to be highly activated in tumor microenvironment and its co-expression network was enriched inPDL1/PD1checkpoint pathway in cancer. Additionally, knockdown ofRUFY4led to the decline ofPDL1and proliferation ability in ccRCC cell lines.ConclusionTFHs and Tregs were considered as prognostic biomarkers andRUFY4was an immunotherapeutic predictor of ccRCC patients in aPDL1-Related manner.