STING1 and neoplasm: Collectively, probiotics’ efficacy in enhancing immunotherapy hinges on three core principles: (1) strain-specific metabolite production (e.g., L. reuteri’s Trp derivatives, A. muciniphila’s bile acid modulations) that aligns with tumor immune needs; (2) activation of conserved immune pathways (cGAS/STING, Th1 polarization) that bridge gut and tumor immunity; and (3) context dependency (tumor type, baseline microbiota) that necessitates precision.