CTLA4 and neoplasm: These processes include, but not limit to, (1) expansion of immunosuppressive cells [regulatory T (Treg) cells and myeloid-derived suppressor cells (MDSCs)] in the tumor microenvironment; (2) elevation of various cytokines and chemokines [e.g., transforming growth factor-β (TGF-β), indoleamine 2,3-dioxygenase (IDO), interleukin (IL)-10]; and (3) co-inhibitory signaling pathways mediated via immune checkpoints [e.g., cytotoxic T-lymphocyte-associated protein-4 (CTLA-4), PD-1, T cell immunoglobulin- and mucin domain-containing molecule-3 (TIM-3), lymphocyte activation gene 3 (LAG3)] [22].