Despite that a DNA demethylating agent can directly enhance activation and cytolytic capacity of CD8+ T cells, in this study, we observed that only a small proportion of CD8+ TILs belonged to tumor-specific clonal T cells after decitabine therapy; while the combination of decitabine and anti–PD-1 contributed to prominent clonal expansion of tumor-specific progenitor Tex. This evidence concerns the gene PDCD1 and neoplasm.