PDCD1 and neoplasm: As mentioned, CRISPR/cas technology has already been used in one clinical trial in solid tumors expressing mesothelin [46] targeting PD-1 and TRAC genes to block tumor inhibitory signaling (PD-1) and to reduce the risk of autoimmune responses as a consequence of PD-1 KO (TRAC), but no improvements in terms of persistence or clinical benefit was registered.