Background: Locoregional recurrence (LRR) is a major cause of death for patients (pts) with squamous cell carcinoma of the head and neck (SCCHN). With therapy options limited by prior treatment, surgery often represents the best chance for disease control. Emerging data suggests a role for neoadjuvant immunotherapy in upfront resectable SCCHN and the importance of NK cells in the tumor microenvironment. We hypothesized that dual immune checkpoint inhibition (anti-PD-1, nivolumab [N] and anti-KIR, lirilumab [L]) before and after salvage surgery would improve 1-year disease-free survival (DFS). Methods: Pts with operable LRR of SCCHN (any HPV or smoking status) with a disease-free interval of > 8 weeks after curative intent therapy were eligible for this phase II trial. Pts received a single dose of pre-op N (240 mg) + L (240 mg) 7-21 days before surgery, followed by 6-cycles of adjuvant N+L on days 1, 15 (N alone) of a 28-day cycle (C) for C1-3; and on day 1 for C4-6. Primary endpoint was 1-year DFS; 37 DFS events among N = 54 pts provided 81% power to detect improvement in 1-year DFS from 57% to 67.5% (one-sided 10% Wald’s test). Secondary endpoints: safety, radiologic response (RECIST v1.1) to pre-op N+L, and overall survival (OS). Correlatives included tumor sequencing, PD-L1 status, and immunoprofiling. Results: Between 3/15/18 and 5/29/20, N = 29 enrolled (stopped due to expiration of drug supply). Among 28 treated pts, median age: 66, 18% (5/28) women, 83% smokers; primary site: 10 oral cavity, 8 oropharynx (5/8 HPV+), and 10 larynx/hypopharynx. 96% (27/28) had prior HN radiation; 71% (20/28) prior chemotherapy. There were no delays to surgery. Grade 3+ adverse events: 11% (3/28); no deaths from treatment. At time of surgery, 96% (27/28) had stable disease radiologically with 3 showing regression, 4% (1/28) had disease progression. Pathologic response to N+L was observed in 43% (12/28): 4/28 (14%) major (tumor viability, TV ≤10%); 8/28 (29%) partial (TV ≤50%). PD-L1 CPS at surgery was similar regardless of pathologic response (p = 0.63). 68% (19/28) completed all 6-cycles of adjuvant N+L; N = 1 came off for toxicity. Ten pts (36%) recurred (local = 8, distant = 2). 5/28 (18%) had positive margins, of which 4 (80%) recurred; 4/28 (14%) declined to start adjuvant N+L, of which 3 (75%) later recurred. At median follow-up of 20.2 months, 1-year DFS70% (95%CI, 48-84%) and 1-year OS: 85% (95%CI, 65-94%). Median tumor mutational burden was 4 (range, 1-11). TP53 was the most frequent alteration (78%, 21/27). CD39 expression by TILs and CD38 expression by circulating CD4/8+ T cells increased after N+L exposure (p < 0.05). Conclusions: Neoadjuvant and adjuvant N+L was safe and well tolerated. We observed a 43% pathologic response rate prior to salvage surgery, with a favorable 1-year DFS of 70% and 1-year OS > 80% among previously irradiated pts. Further evaluation of this strategy is warranted (NCT03341936).