PDCD1 and neoplasm: When the form of the drug administered was changed to an inulin gel, inulin gel plus anti-PD-1 therapy increased the relative abundance of Akkermansia and resulted in an increasing trend in the abundance of Roseburia. Combined treatment can increase the abundance of the beneficial commensal microbiota and SCFA metabolites to increase Tcf1+PD-1+CD8+ T cell numbers and improve CRC tumour burden (Han et al., 2021).