B2M and neoplasm: The in vitro antitumor function of these multiplex double‐knockout (DKO) (TRAC and B2M) and triple‐knockout (TKO) (TRAC, B2M, and PD‐1) CAR‐T cells revealed higher cytokine production and potent cytotoxic activity against tumor cells compared to standard CAR‐T cells.60