Additional Study Information: This study is for patients with recurrent or metastatic Squamous Cell Carcinoma of the Head and Neck (SCCHN). This study will test the safety of an experimental anti-cancer drug (MEDI4736). MEDI4736 is an antibody (a protein produced by the defense system of the body immune system) that has been made in the laboratory. MEDI4736 boosts the ability of your immune system to detect and fight cancer. The levels of study drug in your blood will be measured to see how your body accepts the study drug you will receive. The study will also evaluate whether your immune system becomes activated following treatment and how MEDI4736 works. Samples of your blood or tissue may be used by researchers to learn more about how patients/tumors are likely to respond to treatment with MEDI4736 (this is called biomarker research). Research on how MEDI4736 works may help develop new treatments in the future. Results from this research will be based on information from all of the patients who take part in this study and not just from your samples.