TNFRSF9 and colorectal carcinoma: At the systems level, ILA from L. gallinarum can cooperate with the indoleamine 2,3-dioxygenase (IDO)1/kynurenine/AHR axis to improve anti-PD-1 efficacy by limiting Treg activity in CRC, providing a mechanistic link between ILA-centered epigenetic tuning of DCs and checkpoint responses [111].