Notably, re-colonization of species from these two taxa including Bacteroides thetaiotaomicron, Bacteroides fragilis, and/or Burkholderia cepacia into microbiota-depleted mice rescued CTLA-4 blockade resistance by promoting TH1-mediated immune response and dendritic cell maturation in tumor-draining lymph nodes, meanwhile alleviating anti-CTLA-4-induced colitis. Here, CTLA4 is linked to neoplasm.