For example, stimulation of the PI3K/AKT pathway in tumor cells might result in increased expression of PD-L1,55,56 while the presence of IFN-γ can induce PD-L1 expression as a feedback mechanism to limit immune activation.57 Such as a previous study discovered that CD8-positive lymphocytes secrete Interferon-γ, which enhances PD-L1 expression in ovarian cancer cells, thereby promoting tumor growth and facilitating immune evasion. This evidence concerns the gene CD8A and ovarian carcinoma.