TGFB1 and central nervous system cancer: The core controversy currently faced in the research on glioma–glia cell crosstalk lies in the contradiction of the role of the immune microenvironment: The dynamic balance mechanism between microglia and macrophages in tumor‐promoting polarization (such as TGF‐β‐mediated angiogenesis) and potential antitumor functions (such as antigen presentation) has not been clarified.