Activated NK cells predominantly secrete IFN-γ and GM-CSF [41], whereas CAR-T cells mainly stimulate cytokines such as interleukin (IL)-1a, IL-1Ra, IL-2, IL-2Ra, IL-6, TNF-α, MCP-1, IL-8, IL-10, and IL-15, which are strongly linked to CRS and severe neurotoxicity [42]. This evidence concerns the gene IL2 and congenital rubella syndrome.