IL2 and neoplasm: Oral Akkermansia muciniphila (AKK) triggers antitumor immune responses, induces tumor shrinkage, and prolongs median survival in tumor-bearing mice, and While AKK treatment is successful in lowering the proportion of Treg cells in the TME, AKK alone attracts a higher proportion of CTL than the preadministration of IL-2 combined with AKK. In addition to significantly lowering the proportion of CD133+ cells in tumor tissue and diminishing tumor stem cell-like potency, the combination of IL-2 and AKK is more effective than monotherapy at controlling Treg levels (Table 1) (Shi, et al., 2020a).