Adoptive immunotherapy with T cells expressing chimeric antigen receptors (CARs) for B-cell malignancies serves as a model for identifying subsets with superior clinical activity. We profiled the infusion products (IP) of 9 patients with large B-cell lymphoma (LBCL) using scRNA-sequencing to reveal the therapeutic potential of CD19-specific CAR+ T cells. ScRNA-seq demonstrated that T cells from responders were enriched in pathways related to T-cell killing, migration and actin cytoskeleton, and TCR clustering. Overall design: Leftover CD19-targeted CAR T cells from patients with LBCL were analyzed using scRNA sequencing to determine the differences between the responders and non-responders to the therapy in terms of gene expression. Total of 9 samples: 5 patients with complete response (CR), 2 patients with progressive disease (PD), and 2 patients with partial response (PR) after 3 months of follow-up after the therapy. After a 6-month follow-up, the responses were as follows: 4 patients with complete response (CR), 3 patients with progressive disease (PD), and 2 patients with partial response (PR)