While most bi-functional antibodies are developed to allow interaction between immune and tumor cells, there are other therapeutic strategies, including linking cells to a "payload" (for example, a drug) or blocking signaling pathways in the TME, such as the inhibition of cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and programmed death-1 (PD-1) channels [27]. Here, CTLA4 is linked to neoplasm.