Retrospective evidence supports this trend: in a study of 21 patients with ICI-induced oesophagitis, 15 (71%) received anti-PD-1/PD-L1 monotherapy, 1 (5%) received anti-CTLA-4 monotherapy alone, and 5 (24%) received combination therapy (Kumagai et al., 2024). Here, CTLA4 is linked to esophagitis.