Tumor-associated macrophages (TAMs) have been of great interest in ICB due to their ability to enhance immunosuppression through means of suppressing tumor-infiltrating lymphocytes (TILs), such as direct interactions with PD1 via upregulation of PDL1, or secretion of immunosuppressive metabolites or ligands that promote the recruitment of T regulatory cells (Tregs)19,20. This evidence concerns the gene PDCD1 and neoplasm.