By comparing sgRNAs recovered from subcutaneous xenografts derived from KrasG12D/Trp53−/− mouse lung cancer cells in mice treated with control IgG and anti-PD-1 antibody, several hits were identified, including Tap2, Jak2, Stat1, Catenin Beta 1 (Ctnnb1), Anti-Silencing Function 1A Histone Chaperone (Asf1a), Mitogen-Activated Protein Kinase 3 (Mapk3), and TSC Complex Subunit 1 (Tsc1), that influenced the sensitivity to anti-PD-1 treatment. The gene discussed is MAPK3; the disease is lung carcinoma.