For instance, it has been demonstrated in preclinical research that knocking out programmed cell death 1 (PDCD1) using gene editing technologies, such as clustered regularly interspaced short palindromic repeats-associated protein 9 (CRISPR/Cas9) or transcription activator-like effector nucleases (TALENs), can improve the anti-tumor effect of TIL therapy [10]. Here, PDCD1 is linked to neoplasm.