CTLA4 and neoplasm: Immunotherapeutic aptamers aim to (1) inhibit the action of the immunosuppressive cytokines (like transforming growth factor TGF beta, interleukin IL10) produced within TME by tumor-infiltrating lymphocytes; or (2) to antagonize the main immune checkpoint receptors (like T-cell immunoglobulin and mucin domain 3 TIM-3, programmed cell death 1 PD-1, programmed cell death ligand 1 PD-L1, cytotoxic T-lymphocyte-associated protein 4 CTLA-4); or (3) to co-stimulate T lymphocytes or antigen-presenting cells by binding to receptors such as CD40, CD28, OX40, 4-1BB [11,110].