CD274 and neoplasm: TAMs are also involved in tumor immune microenvironment (TIME) formation through their expression of immune checkpoints such as PD-L1/L2 and CD80/86 that bind to their receptors (PD-1/cytotoxic T- lymphocyte-associated protein 4 (CTLA-4)) that constitutively express on T cells, directly restraining the function of activated anti-tumor T cells (36).