 In this study aims to solve two main problems: one is to improve and try to optimize current protocols of CTC isolations based on the investigator previous work, which is one of most challenging problems in CTC field to date; the other is to understand the status of immune system in HNSCC patients, especially focusing on PD-1-PD-L1 pathway and its expressions. After series basic experiments of immune cell analysis and conditional adjustment of CTC isolation protocols, the investigator are willing to isolate CTCs and immune cells at a single blood drawing at the same time. A prospective trial will be conducted to elucidate the roles of PD-1 expression lymphocytes and CTC numbers on the clinical outcomes of HNSCC patients. 