Squamous cell carcinoma of the head and neck, which accounts for 90% of head and neck cancers, is the tenth most common cancer worldwide with over 650000 new cases per year. The major risk factors for HNSCC development comprise alcohol and tobacco consumption. During the last decades human papilloma virus infection (HPV) has been identified to contribute to the development of oropharyngeal HNSCC in a subgroup of patients5. Standard treatment options include surgery, (chemo)radiation and chemotherapy. Despite improvements of treatment regimens the recurrence rate of stage III/IV disease after curative therapy is about 30-40%. In locoregionally unresectable recurrent or metastatic disease palliative poly-chemotherapy is the mainstay of therapy.The median survival time of these patients is 6-8 months. Based on the results of the EXTREME study a combination regimen containing a platinum drug, 5 fluorouracil (5-FU) and weekly cetuximab has become standard of care in this setting. For patients, who progressed after platinum based therapy, treatment options are scarce. Besides platinum drugs, taxanes such as paclitaxel or docetaxel were shown to be of particular use in this setting. Apart from that there has been increasing preclinical and clinical evidence that immune-checkpoint inhibitors such as pembrolizumab might play a role in HNSCC. Thus, it is the aim of this study to test if the combination of docetaxel and pembrolizumab after platinum failure is an effective and safe regimen.