CD28 and neoplasm: These antibodies exhibit specificity towards a variety of molecules, encompassing immune inhibitory targets like PD-1, CTLA-4, CD73 [315], immune-stimulatory molecules such as OX-40, CD28, and tumor-associated proteins like melanoma-associated antigen (gp100) [316], epithelial cell adhesion molecule (EpCAM) found on tumor cells, CD33 expressed on MDSCs, or Delta-like ligand 3 (DLL3) [317] to facilitate direct lysis of tumor cells or immunosuppressive cells.