Beyond ICIs, ATBs can potentiate adoptive cell therapy: vancomycin, by selectively eliminating Gram-positive commensals, expands systemic CD8α+ DCs and boosts IL-12p70 production—changes tied to increased microbial Trp metabolism and IPA accumulation—which enhances the antitumor activity of CAR-T cells and γδ T cells in lymphoma and melanoma models (111, 276, 277). This evidence concerns the gene CD8A and lymphoma.