In recent years, researchers illustrated that triggering receptor expressed on myeloid cells-2 (TREM2), a transmembrane receptor of the immunoglobulin superfamily, was a crucial pathology-induced immune signaling hub, and more and more evidence suggested that TREM2 played a vital role in tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs). This evidence concerns the gene TREM2 and neoplasm.