HAVCR2 and neoplasm: On the prebiotic side, dietary supplementation with inulin-type fructans enhances anti-PD-1 efficacy in murine tumor models by expanding Faecalibacterium prausnitzii and elevating fecal butyrate, which promotes intratumoral IFN-γ+CD8+ T cell infiltration and reduces exhausted PD-1+TIM-3+ T cells [49].