Notch signaling promotes CD4⁺ CAR T-cell persistence and helper function. Figure shows that culturing of CD4⁺ T cells on fibronectin and anti-Notch1 antibody-coated plates during CAR T-cell transduction and expansion activated Notch signaling. Notch1-activated CD4⁺ CAR T cells produced more proinflammatory cytokines and had enhanced in vivo persistence as well as helper T-cell function in lymphoma xenograft models. Created with BioRender.com.