In a large multi-tumor study conducted by Schalper and colleagues [67], higher pre-treatment levels of circulating IL-8 were associated with poor outcomes in lung cancer, melanoma, and aRCC patients receiving nivolumab, double ICI, everolimus, or docetaxel, which suggests a more prognostic than predictive role (for aRCC, nivolumab OS HR: 2.56, P < 0.001; everolimus OS HR: 2.40, P < 0.001). Here, CXCL8 is linked to neoplasm.