IL6 and neoplasm: First, through the production of secreted suppressive molecules such as transforming growth factor (TGF)‐β, IL‐6, and prostaglandin E2 (PGE2) and, second, through various immunosuppressive cells such as regulatory T cells (Treg), myeloid‐derived suppressor cells (MDSC), tumor‐associated macrophages (TAM), and cancer‐associated fibroblasts (CAF), which are partly induced by the secreted factors mentioned above (Figure 1A‐C).