PDCD1 and head and neck squamous cell carcinoma: Using matched genomic and transcriptomic data, we identify multiple copy number alterations enriched in cold tumours, including deletions in PTEN and amplifications in MYC and EGFR. We show that responses to PD1-blockade are associated with a transcriptional signature for hot tumours post-treatment, while the cold signature, and specifically a gene expression module we previously linked to increased aerobic glycolysis downstream of EGFR in head and neck squamous cell carcinoma (HNSCC)17, is enriched in non-responders.