• Males and females, ages ≥18 years

• Histologically or cytologically confirmed Squamous Cell Carcinoma, previously untreated stage III, or IVA HNC by AJCC 8th edition staging system. Newly diagnosed, never treated HNC cancer but could have had a surgically treated primary \> 5 years previous without radiotherapy or chemotherapy. For HPV positive oropharyngeal cancer, patients with T3 or T4 primary and/or one ipsilateral lymph node greater than 3 cm, multiple ipsilateral lymph nodes, bilateral lymph nodes, or contralateral lymph node will be included. Patients must undergo CT or MRI to rule out the presence of distant metastases.

• Accessible tumor for pretreatment (baseline) open/incisional biopsy to provide adequate correlative specimen.

• Have LAG-3 and PD-L1 results for stratification.

• LVEF assessment with documented LVEF ≥50% by either TTE or MUGA (TTE preferred test) within 28 days prior to first study drug administration

• Women of child-bearing potential (WOCBP) must be advised of the importance of avoiding pregnancy during trial participation and the potential risk factors for an unintentional pregnancy. All WOCBP MUST have a negative pregnancy test within 7 days prior to first receiving investigational product. If the pregnancy test is positive, the patient must not receive investigational product and must not be enrolled in the study. All WOCBP must agree to use appropriate contraception to prevent pregnancy for the duration of treatment with study treatments, plus 24 weeks after the last dose of study treatment (i.e., 30 days \[duration of ovulatory cycle\] plus approximately 5 half-lives).

• All males must agree to use appropriate contraception for the duration of treatment with study treatments plus 33 weeks after the last dose of study treatment (i.e., 90 days \[duration of sperm turnover\] plus approximately 5 half-lives). In addition, male participants must be willing to refrain from sperm donation during this time. In addition, men enrolled on this study must be informed of the risks to any sexual partner of childbearing potential and should practice an effective method of birth control

• Azoospermic males are exempt from contraceptive requirements unless the potential exists for fetal toxicity due to study drug being present in seminal fluid, even if the participant has undergone a successful vasectomy or if the partner is pregnant. WOCBP who are continuously not heterosexually active are also exempt from contraceptive requirements, and still must undergo pregnancy testing as described in this section.

• Primary tumors of the oral cavity, oropharynx, hypopharynx, or larynx will be included.

⁃ Eligible for surgical resection.

⁃ Age ≥ 18 years

⁃ ECOG performance status 0-1.

⁃ Have signed written informed consent