PDCD1 and esophageal squamous cell carcinoma: In SCC patient samples, we identified that TP63 expression is negatively correlated with CD8+ T cell infiltration and the expression of effective cytotoxic markers such as GZMB, GZMK, and PRF1. Supportively, in a phase I clinical trial of ICB therapy (NCT02742935), low expression of TP63 was shown to be enriched in a subset of “immune modulation” ESCC patients, who were more responsive to single PD-1 mAb therapy7.