A Longitudinal Multi-Omic Biomarker Profiling Study of Patients With Head & Neck Squamous Cell Carcinoma (HNSCC)

Inclusion Criteria: * ≥18 years of age * Willing and able to provide informed consent * Histologically- or cytologically-confirmed metastatic or unresectable, recurrent HNSCC unsuitable for local therapies * Intended for first line anti-PD1 or PDL1 monotherapy or combination therapy * Must submit tumor tissue sample representative of current disease per laboratory manual Exclusion Criteria: * Non-squamous histologies (eg, nasopharynx or salivary gland) * Relapse or recurrence within 6 months of first line chemotherapy and / or chemoradiotherapy * Tumors that are PD-L1 negative (CPS \<1) * Clinical evidence of an active second invasive malignancy within \<2 years of enrollment with the exception of stable prostate cancer on watchful waiting, in situ cervical cancer, in situ breast carcinoma or localized non-melanoma skin cancers * Unable to comply with study procedures (i.e., not willing or able to have additional blood samples collected)