The financial industry is evolving to adopt modern core banking systems that can respond and scale to meet customer demand in near-real time. Traditional mainframe-based architectures are being replaced by event-driven streaming data platforms, which enable banks to unlock their critical mainframe data, minimize disruptions, and power their ever-growing landscape of cloud-native applications and systems. The key technologies used in the modern core banking stack include unlocking core banking system of record, enriching data in real-time with Apache Flink, decoupling system of record and system of access with MongoDB, and writing data out to a non-relational DB like Mongo Atlas. Mainframe migrations are being done incrementally, often through connectors like MQ on Z and Oracle CDC, which reduce costs by 90% or more, depending on the solution. The modernization process is slow, iterative, and typically not big bang, with many large financial institutions still in the early innings of this modernization.