CCL2 and neoplasm: The anti-PD-1-treated monotherapy groups had the highest number of positive correlations with tumor burden, with GM-CSF (r = 0.8201), IL-1β (r = 0.8214), IL-2 (r = 0.8297), IL-12p70 (r = 0.8318), CXCL10 (IP-10) (r = 0.8637), CCL2 (MCP-1) (r = 0.8231), and CCL4 (MIP-1β) (r = 0.8239) all reaching statistical significance (p < 0.05).