In CAR-T therapy, the production of IFN-γ was mediated by myeloid-derived macrophages and plays a critical role in CRS pathogenesis.153 Elevated levels of the above core cytokines have been confirmed in patients in clinical146 and in murine models.32 In primary HLH, large quantities of IFN-γ were produced and excessive T cells were activated.154 In COVID-19, numerous studies have reported elevated levels of IFN-γ in patients, which may mainly from macrophages, not T cells. This evidence concerns the gene IFNG and COVID-19.