CD28 and congenital rubella syndrome: Compared with the CD28 costimulatory domain, the 4-1BB-based products showed a better safety profile on any-grade CRS (<i>p</i> < 0.01), severe CRS (<i>p</i> = 0.04), any-grade neurotoxicity (<i>p</i> < 0.01), and severe neurotoxicity (<i>p</i> < 0.01).