To determine the function of exosomal circUSP7 during tumour immune evasion, we isolated exosomes from the culture media of NSCLC cell lines or the normal human bronchial epithelial cell line HBE, incubated these exosomes with CD8+ T cells for 48 h, and then activated the T cells with CD3 antibodies. The gene discussed is CD8A; the disease is neoplasm.