IL13 and neoplasm: Previous studies showed that PD-1 blockade led to the augmentation of effector T cells in tumor sites, increasing the cytolytic activity of tumor-specific cells, increasing production of IL-2, INF-γ, TNF-α, IL-17, and IL-6, and decreasing the production of the Th2 cytokines such as IL-5 and IL-13 [19, 20].