Jason et al. used a CRISPR/Cas9 genome editing screen to identify PD-1-resistant mutants (Ifngr2 and Jak1) in B16.SIY melanoma cells, and they confirmed the importance of IFN-γR signaling in the resistance process in vitro, which plays a great role in the T-cell-mediated tumor cell killing process 64. The gene discussed is PDCD1; the disease is neoplasm.