Wang et al. developed and validated an ML algorithm to predict early (first 50 days) all-cause mortality after umbilical cord blood transplantation (UCBT) in patients with different IEIs [SCID, very early onset inflammatory bowel diseases (VEO-IBD), chronic granulomatous disease (CGD), Wiskott–Aldrich syndrome (WAS), leukocyte adhesion deficiency (LAD), hyper-IgM (HIGM) syndrome] based on pre-transplant risk factors [43]. This evidence concerns the gene CD40LG and Down syndrome.