PDCD1 and neoplasm: More in-deep gene expression and single-cell polyfunctionality analysis after exposure to tumor cells expressing HER2 and physiological PD-L1 levels revealed that whether PD-1 KO induced a significant change in the LA CAR-T cell population at the transcriptomic and functional level, HA CAR-T cells after PD-1 KO remained similar to the mock-electroporated CAR-T cells.