Among the shared pathogenetic mechanisms leading to neurodevelopmental disorders (NDDs), a dysregulated inflammatory response has been described as a convergent pathway in NDDs. This scoping review was registered in the OSF database. It was conducted in accordance with the PRISMA Extension for Scoping Reviews, utilizing a comprehensive literature search of major academic databases, including PubMed and Web of Science. The search was performed until 1 March 2025, using a combination of predefined search terms and Boolean operators (AND, OR) to ensure a comprehensive identification of relevant studies. A comprehensive summary of the evidence on immunological and neuroinflammatory pathways underlying the NDDs is shown. This review also reports evidence on early-onset presentation of schizophrenia spectrum and obsessive–compulsive disorder since clinical researchers are beginning to consider these conditions neurodevelopmental disorders. Furthermore, this review outlines the recently described clinical entity, PANS (Pediatric Acute-Onset Neuropsychiatric Syndrome), and its clinical and pathogenetic contact points with NDDs, delineating a spectrum of disorders that share common pathogenetic pathways. This scoping review improves the awareness of immune/neuroinflammatory correlates supporting NDDs. Furthermore, it suggests adopting a transnosographic approach to neuropsychiatric disorders, including PANS as a syndromic construct that overlaps with NDDs.