PDCD1 and neoplasm: The impact of the tumour immune response has become of increased interest and importance with the introduction of immunomodulatory therapies for the treatment of OSCC, such as Pembrolizumab, that target programmed cell death protein 1 (PD‐1) located on lymphocytes, which is a receptor for programmed death ligand 1 (PD‐L1) [4].