PDCD1 and neoplasm: Finally, we observed accelerated tumor clearance by PD-1 edited CAR T cells relative to controls (Supplementary Fig. 8a,b) when animals with smaller initial tumors (50–100 mm3) were treated with a larger number of CAR T cells (5 × 106 CD4+ CAR+ and 5 × 106 CD8+ CAR+ cells), although we noted that both un-edited and edited cells were able to clear CD19+ PD-L1+ tumors at this low tumor burden and high T cell dose.