CD274 and neoplasm: This is a single‐blind prospective study evaluating changes in PD‐L1 expression in tumor‐associated cells in blood samples before (T0) and after (T1) treatment with ICI (ICI, 41 individuals) or without ICI (no ICI, 41 individuals). Among patients treated with ICI, those with increased PD‐L1 expression between T0 and T1 had significantly better PFS (HR, 3.49; 95% CI, 1.5–8.3; p = 0.0091) and OS (HR, 3.058; 95% CI, 1.2–7.9; p = 0.0410).