Inspired by the intrinsic antibacterial function of Doxy, Doxy@CaCO3-PEG could also potentiate the therapeutic efficacy of Tet-HER1-CAR-T cells against immunosuppressive Fusobacterium nucleatum (F.n.)-colonized HER1-overexpressing TNBC patient-derived tumor xenografts (PDXs). The gene discussed is EGFR; the disease is neoplasm.