Plasma levels of CSF-1 were found to be higher in patients resistant to ICI therapy (8898 vs. 14031 pg/mL, p < 0.001). Higher levels of CSF-1 were associated with poor therapy response (RR = 7,944; p = 0.013), disease progression (RR = 8.556; p < 0.001), and shorter survivals (PFS, 50 days vs. 305 days; p < 0.001; OS, 248 days vs. 1369 days, p < 0.01).