CD4 and neoplasm: Ferroptosis is a unique form of cell death that relies primarily on accumulating irons and lipid peroxides within the cell.[48] Ferroptosis is closely related to the immune microenvironment.[49] In the tumor microenvironment, tumor‐associated macrophages mainly exhibit immunosuppressive M2 phenotype, which is sensitive to ferroptosis, while M1‐type macrophages are resistant to ferroptosis.[50] In addition, the cell communications analysis showed that OASL1+ macrophage enhanced their interaction with other subtypes of macrophages, but weakened their interaction with CD8 Tex and CD4 Treg.