In an era where over 70% of CSPs struggle with fragmented data and static customer profiles, the AI Marketing Brain introduces a transformative solution. By leveraging a Large User Model (LUM) built on Graph Neural Networks (GNNs) and Transformer-based AI, this Catalyst enables real-time, hyper-personalized marketing strategies. The system integrates multi-domain data (e.g., CRM, billing, network usage) to predict user behavior, automate campaign execution, and optimize pricing dynamically. Unlike traditional marketing, which relies on manual workflows and delayed analytics, the AI Marketing Brain reduces decision latency to seconds, driving measurable outcomes like 18% ARPU growth in 5G upselling trials. This project aligns with TM Forum’s DT4DI standards, ensuring scalability across 2B/2C scenarios while addressing privacy compliance through synthetic data training. CSPs face a critical challenge: declining customer retention rates and stagnant revenue growth amid rising operational costs. For example, Telkomsel’s 5G adoption campaigns previously failed due to generic targeting and delayed feedback loops. As one executive noted, “Our marketing teams were working with last year’s data, while user behavior evolved in weeks. We needed a system that could predict churn and act before it happened.” The AI Marketing Brain directly addresses this by enabling proactive, data-driven decisions. For B2C scenarios, it reduces manual effort by 40% while increasing campaign ROI. For B2B, it streamlines FMC (Fixed-Mobile Convergence) scenarios by integrating enterprise usage patterns with consumer behavior. Solving these pain points will allow CSPs to shift from reactive cost centers to agile, revenue-generating departments.