In a high lactate environment, the lactate concentration difference formed inside and outside the cell prompts extracellular lactate to enter the cell by diffusion through MCT1 or other transporters on T cells as well as transporter-independent diffusion, leading to an intracellular low pH environment that prevents the upregulation of nuclear factor of activated T cells (NFAT) in T and NK cells, which leads to the reduction of interferon-γ (IFN-γ) and affects the activation of T cells and the participation in the process of tumor immunosurveillance. The gene discussed is IFNG; the disease is neoplasm.