S100A9 and melanoma: Based on the classical marker genes,[15, 16] these cells were categorized into seven distinct cell types: melanoma cells (Slc45a2, Sox10, Tyr, Mlana, S100a1, Mitf, and S100b), macrophages (Cd68 and C1qa), T/NK cells (Cd3e, Cd3d, Ccl5, and Nkg7), fibroblasts (Lum and Pdgfra), monocytes (Cd14 and S100a9), endothelial cells (Pecam1), and other cells (Figure 2A,B).