CD274 and melanoma: The oral administration of Bifidobacterium in combination with anti-PD-L1 therapy almost completely eliminates melanoma.461 Colonization of mice with a mixture of 11-low-abundance bacteria (seven of which are Bacteroidetes) isolated from healthy human donors remarkably strengthens the ICI efficacy without causing side effects (such as inflammation).43 However, these promising experimental results are limited to animal studies.