Threat modeling, transitioning from theoretical to practical application, is essential in identifying and mitigating vulnerabilities in fast-paced CI/CD environments, ensuring development velocity and software supply chain security. This text explores various methodologies, such as STRIDE, PASTA, and Agile Threat Modeling, demonstrating their integration into automated development workflows like Mergify's merge queue, allowing teams to deconstruct workflows, identify attack vectors, and implement security controls. By applying these techniques, from data flow diagram analysis to persona-based threat modeling, the focus shifts to proactive security within the development lifecycle, fostering a culture of continuous assurance and empowering developers to act as defenders. The text emphasizes the importance of embedding these practices into CI/CD pipelines to transform them into sophisticated security checkpoints, thus securing every commit and accelerating development by addressing issues early.