In the context of immunological synapse dynamics, tumor cells and their microenvironment underpin specificity and complexity of immune responses through secretion of immunosuppressive soluble factors, such as indoleamine-2,3-dioxygenase-1 (IDO1), PD-L1, and IL-10 (47–50), and recruitment of immunosuppressive cells, such as tumor-associated macrophages and myeloid-derived suppressor cells (51). The gene discussed is IDO1; the disease is neoplasm.