The accrual halt will be lifted once the data has been reviewed and there has been a reassessment of available safety information prior to reopening the study to accrual and allowing the study to proceed. 3.3.4 Dose Modification During DLT period dose modifications are not allowed. HPV vaccine: Vaccine doses will not be modified for an individual participant but doses may be skipped per investigator discretion. Once a dose is given to a participant that will always be the dose of vaccine they receive during this trial. M7824: Dose reductions are not allowed but doses may be skipped per investigator discretion. 3.3.5 Toxicity Management Table 2 Treatment Modification Guidance for Symptoms of Infusion-Related Reactions including Immediate Hypersensitivity Infusion-Related Reactions (IRR) are an important risk for M7824. NCI-CTCAE Grade Treatment Modification Grade 1 - mild Mild transient reaction; in general, infusion interruption not indicated; intervention not indicatedIncrease monitoring of vital signs as medically indicated as participants are deemed medically stable by the attending Investigator. Hold infusion if deemed necessary by the investigator. 33 Abbreviated Title: Combo Immunotx in HPV OPSCC Version Date: 04.25.2023 NCI-CTCAE Grade Treatment Modification Grade 2 – moderate Therapy or infusion interruption indicated but responds promptly to symptomatic treatment (for example, antihistamines, nonsteroidal anti-inflammatory drugs, narcotics, IV fluids); prophylactic medications indicated for  24 h.Stop the infusion of the study intervention. Increase monitoring of vital signs as medically indicated as participants are deemed medically stable by the attending Investigator.