JCO In the investigator-sponsored randomized phase II NIVAHL trial for early-stage unfavorable classical Hodgkin lymphoma (HL), two schedules of four cycles of nivolumab, doxorubicin, vinblastine, and dacarbazine followed by 30 Gy involved-site radiotherapy resulted in high complete remission rates and an unprecedented 1-year progression-free survival in 109 patients. In this article, we report the preplanned final analysis conducted three years after the registration of the last patient including long-term safety results. No survival events were observed since the primary analysis, and after a median follow-up (FU) of 41 months, the overall survival was 100% in both treatment groups. The progression-free survival was 98% and 100% in the sequential and concomitant nivolumab, doxorubicin, vinblastine, and dacarbazine treatment groups, respectively. At last FU, the mean forced expiratory pressure in one second was 95.5% (standard deviation 12.7%), the mean diffusion capacity for carbon monoxide adjusted for hemoglobin was 82.8% (standard deviation 15.4%), and the left ventricular ejection fraction was in the normal range in 95% of patients. Hypothyroidism requiring long-term medication occurred in 15% of patients, who were nearly exclusively female (87%). No second primary malignancies occurred, and no patient required corticosteroid treatment at last FU. Patient-reported normalized global quality-of-life score measured by European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30 improved over time. This preplanned FU analysis of the largest anti-programmed death protein 1 HL first-line trial to date confirms the outstanding efficacy and relatively favorable safety profile of this therapeutic approach.