CD4 and renal cell carcinoma: Interestingly, fecal microbiota transplantation (FMT) from RCC ICI responders, or FMT from non-responders with additional A. muciniphila or Bacteroides salyersiae supplementation, restored ICI activity in antibiotic-treated and germ-free mice in an IL-12- and CCR9 + CXCR3+ CD4 T cell-dependent manner [144,145].