Immunohistochemical examination by immunoperoxidase or other labelled antibody techniques using the programmed cell death ligand 1 (PD‑L1) antibody of tumour material from a patient diagnosed with: (a) non‑small cell lung cancer; or (b) recurrent or metastatic squamous cell carcinoma of the oral cavity, pharynx or larynx; or (c) locally recurrent unresectable or metastatic triple-negative breast cancer.