Single-cell analysis reveals that dysfunctional 41BB CAR T cells are a unique terminal state. (A) Uniform manifold approximation and projection (UMAP) of 19/28 and 19/BB cells over time. (B) Proportion of each cluster present in each sample. (C) CD8A expression in each cluster. (D) Reclustering of CD8A-expressing 19/28 and 19/BB cells from days 0, 6, and 15. (E) Pseudotime analysis of CD8 cells. (F) Mapping of CD8 clusters onto pseudotime. (G) Proportion of each sample contained in terminal CD8 clusters 0 and 1.