CTLA4 and esophageal squamous cell carcinoma: CD8 Tex with elevated expression of multiple inhibitory receptors (PDCD1, CTLA4, LAG3, TIGIT, HAVCR2) and Tregs with high expression levels of FOXP3, TIGIT, and CTLA4 (Supplementary Figure S1C) were enriched in the ESCC TME (Figure 1F), which contributed to tumor immune escape and immunotherapy resistance (39, 43).