PDCD1 and neoplasm: It has been proposed that, based on having either relatively high or low immune cell infiltration, tumours may be immunologically classified into ‘hot’ (inflamed) or ‘cold’ (non-inflamed) phenotypes, respectively.35–37 Accordingly, clinical evidences showed that patients with an immunogenic TME had a better clinical response to anti-PD-1/PD-L1 immunotherapies.16 Therefore, we first examined CD8+ T-cell infiltration in HCC tumours with different PD-L1 expression patterns.