Cortex and Thanos, two open-source projects designed to scale Prometheus, have evolved to collaborate closely, leveraging each other's strengths to enhance their capabilities. Initially, Cortex aimed for high scalability and performance, while Thanos prioritized operational simplicity and cost-effectiveness. Over time, they learned from each other, with Thanos adopting a push-based model and Cortex simplifying its operations. Their collaboration has involved shared improvements, such as the integration of caching techniques and configuration optimizations, and the development of the Cortex blocks storage, which utilizes Thanos components. This partnership has not only enhanced both projects but also contributed to the broader open-source community, demonstrating the value of collaboration in overcoming technical challenges and fostering innovation.