A previous melanoma study identified a negative association between TP53-associated aneuploidy and response to CTLA-4 inhibitors (42), while studies in non–small cell lung cancer and esophagogastric adenocarcinoma tissue have found TP53 and HR mutations predicted response to immune checkpoint blockade (43, 44). Here, TP53 is linked to gastroesophageal junction adenocarcinoma.