CD274 and neoplasm: Hypothetically, breaking the PD‐1‐PD‐L1 checkpoint through the action of anti‐PD‐1 antibodies could release T cells, which can then engage with the increased level of MHC class I gene expression on the tumour cell via the T‐cell receptor, leading to increased levels of cytotoxicity and tumour cell killing (Fig. 5C).