Fig. 2

The schematic presentation of the TME composition. The tumor microenvironment (TME) contains both cellular and non-cellular components. Multiple cell types are present in the TME, including cancer cells and stromal cells. The heterogeneous cells contain both immunostimulatory and immunosuppressive subsets that exert anti-tumor and pro-tumor effects, respectively. And the preponderance of the pro-tumor cell subsets contributes to the immunosuppressive TME, leading to cancer progression and the failure of ICB. The application of single-cell RNA sequencing (scRNA-seq) provides insights into TME heterogeneity. Th1 cell, CD4⁺ T helper 1 cell; NK cell, natural killer cell; TAM, tumor-associated macrophage; TAN, tumor-associated neutrophil; Th2 cell, CD4⁺ T helper 2 cell; CAF, cancer-associated fibroblast; Treg, CD4⁺ regulatory T cell; MDSC, myeloid-derived suppressor cell; ECM, extracellular matrix. Created with Figdraw (www.figdraw.com)