CT of the neck and chest. Clinical laboratory tests* 24 Abbreviated Title: Neoadjuvant IO for HNSCC Version Date: August 31, 2022 Serum Chemistries: oAcute care panel (Na+, K+, Cl-, total CO2, creatinine, glucose, blood urea nitrogen) oHepatic panel (AST/GOT, ALT/GPT, total bilirubin, direct bilirubin oMineral panel (albumin, calcium total, magnesium total, phosphorus) oHematology: complete blood count (CBC) with differential and platelets oUrinalysis oSerum pregnancy test (β-HCG) for females of childbearing-potential and women < 12 months since the onset of menopause (within 3 days prior to enrollment). oHBV, HCV, HIV testing including viral load for HCV and HIV (within 3 months prior to enrollment). CD4 testing may also be required for HIV+ patients Histologic confirmation for p16 negativity* if the primary tumor is oropharyngeal (at any time point prior to enrollment). If there is no available tumor sample or pathology report, a biopsy will be performed to confirm the diagnosis using immunohistochemistry for p16. The E6H4 anti-human P16 antibody clone will be used to stain FFPE tissues using standard deparaffinization, staining and mounting techniques. * Outside test results are acceptable if performed in designated time frame(s) listed above.