According to a mouse cancer paradigm, A. muciniphila taken orally following transplantation of fecal microbiota in mice not responding to therapy restored the efficacy of PD‐1 inhibition in an interleukin‐12‐dependent fashion by attracting CCR9 (C‐C chemokine receptor type 9) + CXCR3 (C‐X‐C chemokine receptor 3) + CD4 + T cells into cancer.7 Here, CD4 is linked to cancer.