CAR‐T‐OPENIA is not limited to studies in B‐cell lymphoma but were commonly reported, of grade 3–4, in the two B‐cell maturation antigen (BCMA) directed CAR T‐cell trials for relapsed/refractory multiple myeloma as detailed in Table 1 [6, 7]. The gene discussed is TNFRSF17; the disease is B-cell non-Hodgkin lymphoma.