Due to insufficient antigen immunogenicity, dysregulation of antigen presentation, irreversible T-cell exhaustion, resistance to IFN-γ signaling, and an immunosuppressive tumor microenvironment (TME), tumors can prevent the antitumor efficacy of T cells by forming an unfavorable TME, which leads to primary drug resistance and avoids tumor rejection. The gene discussed is IFNG; the disease is neoplasm.