Immune checkpoint inhibitors are monoclonal antibodies that enhance anti-tumour T-cell-mediated immune responses by releasing their suppression by immune-checkpoints like cytotoxic T-lymphocyte-associated protein 4 (CTLA-4; e.g. ipilimumab) [16,17] or programmed death-1 (PD-1) receptor (e.g. nivolumab, pembrolizumab) [18–21]. Here, CTLA4 is linked to neoplasm.