The cerebellum is increasingly recognized for its crucial role in high-level cognitive processes, particularly in the domain of social cognition and action prediction. Disruptions in cerebellar circuits can lead to significant impairments in anticipating others' intentions and behaviors, affecting daily social interactions. This randomized, double-blind, sham-controlled trial protocol investigates the combined effects of personalized cerebellar High-Definition transcranial Alternating Current Stimulation (HD-tACS) and Immersive Virtual Reality (IVR) training on social prediction abilities. The study involves two clinical populations: adolescents and young adults with congenital cerebellar malformations (CM) and adults with acquired neurodegenerative cerebellar atrophy (CA). Participants undergo eight daily sessions of IVR training designed to enhance internal models of social events through interactive scenarios. Simultaneously, they receive either active or sham HD-tACS delivered at their Individual Gamma Frequency (IGF), determined via baseline EEG. The primary outcomes include behavioral responses to context-based social prediction tasks (action intentions, emotions, and personality traits). Secondary outcomes encompass electrophysiological measures, neuropsychological functioning, and adaptive behavior. By integrating neuromodulation with embodied virtual experiences, the project aims to facilitate cerebello-cerebral plasticity and provide a novel transdiagnostic rehabilitative approach for socio-cognitive impairments.