CTLA4 and neoplasm: The immunosuppressive TME consists of immunosuppressive cells such as regulatory T cells (Tregs), tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), myeloid-derived suppressor cells (MDSCs), tumor-associated fibroblasts (CAFs), extracellular matrix, suppressive cytokines such as interleukin 10, interleukin 17, TGF-β exosomes and immune checkpoint molecules such as PD1, PD-L1, and CTLA4 (Zhang et al., 2019; Li et al., 2020; Nakamura and Smyth, 2020).