CD274 and neoplasm: Although our understanding of the role of PD-1 and PD-L1 on tumour and immune cells continues to evolve (Juneja et al, 2017; Lau et al, 2017), it is generally accepted that successful anti-tumour immune responses following PD-1/PD-L1 blockade require reactivation and clonal-proliferation of antigen-experienced T cells present in the TME (O'Donnell et al, 2017; Sharma et al, 2017).