CD274 and neoplasm: The bladder tumor microenvironment is characterized by a highly immune-suppressive milieu, including the accumulation of various types of immune cells with immunosuppressive phenotypes, such as regulatory T cells (Tregs), tolerogenic dendritic cells (tDCs), and tumor-associated macrophages (TAMs), along with an increased expression of programmed death-ligand 1 (PD-L1) and abnormal metabolism [4,5,6].