Background: Aryl hydrocarbon receptor nuclear translocator like 2 (ARNTL2) pertain to the PAS superfamily. Emerging evidences have demonstrated the carcinogenic roles of transcription factor ARNTL2 in human malignancies, while its roles in ccRCC remain elusive. We sought to explore the comprehensive roles of ARNTL2 in ccRCC and place major emphasis on its correlations with tumor immunity.Methods: The available data from GEO, TCGA and GTEx database were combined with our ccRCC patient tissues to verify the upregulation of ARNTL2, Kaplan–Meier survival curve analysis, Cox regression analyses (including univariate and multivariate) were utilized to evaluate the prognostic values of ARNTL2, the potential biological mechanisms of ARNTL2 were analyzed by using GSEA method. The ssGSEA and xCell algorithm were employed to assess the correlations of ARNTL2 expression with tumor immune microenvironment (TIME), The spearman analyses were applied to investigate the relationships between ARNTL2 expression and the tumor mutational burden (TMB), PD-L1 expression and microsatellite instability (MSI) in pan-cancer.Results: ARNTL2 was overexpressed in ccRCC and increased ARNTL2 expression strongly linked to advanced clinical stage and unfavorable overall survival. ARNTL2 was recognized as an independent prognostic marker through cox regression analyses. A prognostic nomogram was subsequently constructed to predict 1-, 3- and 5-year overall survival via integrating ARNTL2 expression with other clinicopathologic variables. GSEA analysis revealed that the focal adhesion, T cell receptor, cell cycle and JAK-STAT signaling pathway were remarkably enriched in high ARNTL2 samples. xCell analysis suggested that high expression of ARNTL2 exhibited an immune infiltration status similar to CD8+ inflamed ccRCC subtype, which characterized by a high infiltration level of CD8+ T cell and elevated expression level of the immune escape biomarkers such as PD-L1, PD-L2, PD1 and CTLA4. Further pan-cancer analysis indicated that ARNTL2 was tightly linked to TMB, MSI, PD-L1 expression, tumor immunity and poor OS in diverse cancer types.Conclusions: ARNTL2 is an independent adverse predictor of ccRCC patient survival and tightly linked to TMB, MSI, PD-L1 expression and immunity.