Increased levels of IL-6 (75th percentile=P75), IL-7 (P75), IL-8 (P50) and VEGF (P50) were significantly negatively associated with survival (IL-6: HR=2.44, p=0.0112; IL-7: HR=2.38, p=0.0123; IL-8: HR=2.80, p=0.0045, and VEGF: HR=2.43, p=0.0133). 4-1BB (P50) was associated with improved OS (HR=0.39, p=0.0375). Higher levels of IL-8 (P50) and VEGF (P50) were associated with worse PFS (IL-8: HR=2.50, p=0.0133, and VEGF: HR=1.96, p=0.0132) and worse ORR (IL-8: p=0.013, and VEGF: p=0.044)....Higher baseline plasma levels of IL-6, IL-7, IL-8 and VEGF were significantly associated with worse survival outcomes in mRCC pts treated with nivolumab within TRAINING cohort of the NIVOREN trial. In contrast, 4-1BB was significantly associated with improved OS. IL-8 and VEGF were also associated with worse PFS and ORR.