Despite these remarkable response rates, approximately 30% to 50% of patients treated with single-target CD19 CAR-T cells relapse within 1 year, including with CD19+ and CD19− relapse [3,4,5], and particularly among patients characterized by high-risk factors such as double-hit lymphoma, high tumor burden, and presence of a TP53 mutation [4,5,6]. Here, CD19 is linked to lymphoma.