Atherosclerosis is considered an irreversible process, with crucial contribution of inflammation and immune cells. Impact of cancer immunotherapy on a partly immune-driven disease, such as atherosclerosis, is poorly understood, but preclinical models suggest its worsening on programmed death/ligand-1 (PD-1/PD-L1) inhibitors. In a previously reported cohort of 11 patients with non-small cell lung cancer (NSCLC) treated with nivolumab and pre-existing complicated atheromatous plaques, 3 patients had a dramatic radiologic reduction of aortic plaques while on nivolumab; of these 3, 2 died receiving no further treatment. The remaining patient was an 83-year-old woman with history of arterial hypertension and hypothyroidism who was diagnosed with locally advanced squamous NSCLC. At relapse, complicated aortic atheromatous plaques were demonstrated on scans. The patient was then treated with nivolumab obtaining stable disease at radiological assessment, which also demonstrated almost complete vanishing of aortic plaques. After relapse and interval treatment with chemotherapy, she experienced new development of aortic atheromatous plaques. At further relapse she received atezolizumab, which yielded disease response and new reduction in aortic plaques, until nearly complete resolution. The observation of a repeated improvement of atheromatous plaques on treatment with PD-1/PD-L1 inhibitors favors the protective role of T cells on atheromatous plaques that is impaired by PD-L1 expression by plaque-associated macrophages. Validation by independent and prospective observation is needed.