Duane Hamilton, LTIB, NCID1, 8, 15, 21-28, D105 Whole blood for PBMC Study of peripheral immune cell accumulation and function by flow cytometry 5.1.6Flow cytometryDr. Renee Donahue, LTIB, NCID1, 8, 15, 21-28, D105Whole blood for PBMC8 (10 mL) sodium heparin green top tubes Analysis of cytokine concentrations 5.1.7 ELISA or multiplexed assays (e.g. Mesoscale, Luminex, cytokine bead array).Dr. James Hodge, LTIB, NCID1, 8, 15, 21-28, D105Serum 2 (8 mL) SST tubes *Please note that tubes and media may be substituted based on availability with the permission of the PI or laboratory investigator. 43 Abbreviated Title: Neoadjuvant IO for HNSCC Version Date: August 31, 2022 The amount of blood that may be drawn from adult patients for research purposes shall not exceed 10.5 mL/kg or 550 mL, whichever is smaller, over any eight-week period. Blood samples will be processed and stored through the Clinical Services Program with Leidos Biomedical research, Inc.