CD40 and myeloid sarcoma: 2015; Bello‐Morales et al. 2021). Both MS patients and mouse models exhibit changes in gut microbiota, disruption of intestinal barriers, and decreased levels of bile acid metabolites. Fecal microbiota transplantation and bile acid supplementation are promising treatment options (Bhargava et al. 2020; Camara‐Lemarroy et al. 2018). Meanwhile, targeting the gut microbiota to mitigate anti‐CD40‐induced immunosuppressive toxicity highlights the potential role of CD40 in MS pathology by regulating bile acid metabolism (Blake et al. 2021).