IL6 and congenital rubella syndrome: This observation is an agreement with several reports showing that disease burden is among the most important predictors of severe CRS after CAR‐T cell therapy or bispecific T‐cell engager administration.26, 27, 28, 29 All together these observations may help identify patients at higher risk for life‐threatening CRS and develop models for prevention (such as BM graft for patients with active disease status or class II HLA mismatch) or early intervention (for instance, with anti‐IL6 antibody) at the first signs of CRS in patients at higher risk of CRS.