In 2018, the pioneering discoveries of Dr James Allison and Dr Tasuku Honjo on cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death protein 1 (PD-1) led to a surge in research and clinical application of ICIs, resulting in a notable enhancement in anti-tumour efficacy in patients with advanced solid tumours. Here, CTLA4 is linked to neoplasm.