KIR2DL3 and head and neck squamous cell carcinoma: The results of the pan‐carcinoma analysis suggested that the KIR2DL gene family was upregulated in most tumours, including adrenocortical carcinoma, bladder urothelial carcinoma, cervical squamous cell carcinoma, endocervical adenocarcinoma, oesophageal carcinoma, head and neck squamous cell carcinoma and kidney renal clear cell carcinoma.