Butyrate, a SCFA, exemplifies this mechanism by enhancing histone H3K27 acetylation at the PDCD1 and CD28 promoters in CD8+ T cells, thereby elevating PD-1 expression and amplifying anti-PD-1 therapeutic responses in non-small cell lung cancer (NSCLC) (109). The gene discussed is PDCD1; the disease is non-small cell lung carcinoma.