27% cancer patientsb who took antibiotics before or soon after starting the PD-1 blockade therapy had shorter progression-free survival and overall survivalA. muciniphila was found enriched in those patients who respond to anti-PD-1 therapyA. muciniphila alone was able to restore the anti-tumor effects of PD-1 blockade that was inhibited by antibiotics. The gene discussed is PDCD1; the disease is neoplasm.