If a patient’s condition precludes safe performance of any protocol-indicated procedure, the procedure may be canceled at the discretion of the investigator. 27 Abbreviated Title: Neoadjuvant IO for HNSCC Version Date: August 31, 2022 3.1.1 Design Schema  Staggered enrollment for Arm B and Arm C In order to minimize exposure to unanticipated adverse events for the first in human combinations administered to patients in Arm B and Arm C, staggered enrollment will be utilized for the first 3 patients enrolled to Arm B and Arm C. For Arms B and C: An interval of 1 weeks without a DLT must pass between treatment of patient #1 and patient #2. An interval of 1 weeks without a DLT must pass between treatment of patient #2 and patient #3. 28 Abbreviated Title: Neoadjuvant IO for HNSCC Version Date: August 31, 2022 An interval of 1 weeks without a DLT must pass between treatment of patient #3 and patient #4. 3.1.2 Dose Limiting Toxicity Dose-limiting toxicity (DLT) will be defined as any event at least possibly attributable to investigational agents that delays planned tumor resection surgery by >4 weeks or any one of the following adverse events, possibly attributable to study agents (M7824 and/or N-803 and/or TriAd vaccine), that occurs within 28 days after study agent administration. Any grade ≥ 4 hematologic toxicity or grade ≥ 3 anemia or grade 3 thrombocytopenia (platelets 25-50,000) with associated bleeding, except CD4 lymphocyte count or other T lymphocyte subset count. Any grade ≥ 3 non-hematologic toxicity, except for any of the following: otransient (≤ 48 hour) grade 3 fatigue, local reactions, flu like symptoms, fever, headache, or nausea, emesis, and diarrhea not controlled with adequate medical management, or oAny CTCAE Grade 3 skin toxicity lasting less than five days. oElectrolyte abnormalities that can be easily managed with replacement therapy. Grade 3 hyperkalemia/hypokalemia that does not resolve to ≤ Grade 2 within 48 hours-72 hours with medical management will be considered a DLT. oAsymptomatic Grade 3 lipase or amylase elevation. oGrade 3 immune-related colitis or pneumonitis that resolves to grade 1 within 48 hours of initiating appropriate medical treatment oAny endocrinopathy that can be medically managed with hormone replacement Since patients in this population undergo potentially curative resection, a treatment-related delay in planned surgery >4 weeks past the scheduled date will be considered a DLT. This is consistent with other neoadjuvant studies of checkpoint inhibitors in HNSCC patients. 3.1.3 Study Stopping Rule Accrual will be halted if there is an occurrence of one grade 5 toxicity or two grade 4 toxicities in a given arm that are at least possibly attributable to the treatment regimen. This does not apply to asymptomatic grade 4 lab abnormalities (e.g.