CD274 and neoplasm: To further suppress the immune response, cancer cells may exploit the ICI system by expressing specific ligands on their surface, such as the PD-L1 or B7 compound family, which bind to corresponding receptors on the T cells and inhibit their anti-tumour activity (Steven et al. 2016; Dobosz and Dzieciątkowski 2019; Oiseth and Aziz 2017).