CD4 and esophageal squamous cell carcinoma: In addition, PD1hi CD200low CD4 and PD1hi CD200hi CD4 exhausted T‐cell subsets were also isolated from the blood of 18 bladder cancer patients, 10 non‐small cell lung carcinoma patients and 8 esophageal squamous cell carcinoma patients by magnetic sorting (Figure S1I).