On the other side, Yu and colleagues found that IFN-γ induces tumour resistance to anti-PD-1 immunotherapy in BC [55], and experiments on BC cells demonstrated that IFN-γ could upregulate the expression of PD-L1, promote cell migration and transmission, and facilitate the epithelial–mesenchymal transformation of breast cancer cells [56]. The gene discussed is IFNG; the disease is breast cancer.