Cachexia index in predicting outcomes among patients receiving immune checkpoint inhibitor treatment for metastatic renal cell carcinoma

•We found that cachexia index (CXI) was a robust clinical marker for predicting the survival in mRCC patients treated with nivolumab.•In patients with CXI ≥ median, mOS was 48 months (HR 7, 95% [CI] 1.9-26, p = 0.003).•In patients with CXI ≥ median, mPFS was 17 months (HR 2.6, 95% [CI] 1.3-5.3, p = 0.007).•We conclude that CXI, a combined indicator of basic skeletal muscle mass and chronic inflammation, could serve as a useful marker to predict ICI-based treatment outcomes.