reported that PD‐1 deficient anti‐CD19 CAR‐T cell‐mediated killing of tumor cells in vitro was increased, as was the elimination of PD‐L1‐expressing tumor xenografts in vivo, which proved that the PD‐1 disruption could enhance anti‐tumor efficacy of CAR‐T cell therapy (Figure 6C).[132] Hu et al. Here, CD19 is linked to neoplasm.