A preclinical study reported a first CAR-Treg concept aimed at a pathogenic form of α-synuclein in Parkinson’s disease. In two mouse models, engineered regulatory T cells recognizing α-synuclein reduced T cell–mediated inflammation, limited neurodegeneration, and improved motor performance. The approach uses CAR recognition to steer immunosuppression toward disease-linked α-synuclein species, with the investigators framing inflammation control as the lever behind neuroprotection. For Parkinson’s, the work aligns with a growing focus on immunomodulation rather than purely neuron-centric interventions. Because the data are in animals and involve engineered cells, clinical translation remains uncertain; however, the study provides a concrete target hypothesis—pathogenic α-synuclein—and a method for localized immune regulation. The next key step will be whether the strategy can achieve sustained benefit without broad immune suppression in more relevant models, including questions around safety, persistence, and the specificity of α-synuclein recognition.