PDCD1 and head and neck squamous cell carcinoma: A case report of a patient with head and neck squamous cell carcinoma described that treatment with the anti-PD-1 antibody nivolumab caused an increase in antibody production to the tumor antigen NY-ESO-1 and increased plasma cytokine and chemokine levels, although levels decreased with continued anti-PD-1 antibody treatment [11].