More recently, targeted agents in the form of monoclonal antibodies have been used in combination with conventional chemotherapy, agents that were designed to target programmed cell death protein 1 (PD-1), which is often overexpressed in tumour cells, or the epidermal growth factor receptor (EGFR), which is also overexpressed in 90% of HNC patients and is associated with poor outcomes [36]. Here, PDCD1 is linked to neoplasm.