In a clinical setting, positive effects (dense tumor infiltration with effector T cells, decreased Treg and myeloid-derived suppressor cell numbers, and increased IFN-γ production by CD4+ and CD8+ tumor-infiltrating lymphocytes) of recombinant vaccinia and HSV, and of measles virus on the tumor microenvironment were demonstrated in melanoma and cutaneous T cell lymphoma patients [56,57,58,59]. The gene discussed is CD4; the disease is neoplasm.