Solid tumors are not merely collections of malignant cells but complex ecosystems comprising tumor cells, stromal cells, and the extracellular matrix (ECM). The tumor microenvironment (TME) fosters immunosuppression through tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs), and cancer-associated fibroblasts (CAFs), while physical barriers such as dense ECM and abnormal vasculature hinder drug penetration