Mechanistically, sialoglycan ligands, such as CD24 on tumor cells, activate the Siglec‐G‐SHP2 axis in CD8+ T cells, impairing metabolic reprogramming from oxidative phosphorylation to glycolysis, which dampens cytotoxic T lymphocyte (CTL) activation, expansion, and cytotoxicity. This evidence concerns the gene PTPN11 and neoplasm.