It is well known that PD‐1/PD‐L1 is a key regulator of T cell function, and PD‐1/PD‐L1 blockage showed a positive anti‐tumor effect; therefore, the anti‐tumor efficacy of the CAR‐T cell depletion of PD‐1 by the CRISPR/Cas9 gene‐editing technique was significantly improved [140]. This evidence concerns the gene PDCD1 and neoplasm.