Pulumi's CrossGuard tool provides a comprehensive framework for implementing Policy as Code, allowing users to define infrastructure policies using TypeScript or JavaScript, which facilitates automated testing, deployment, and version control. CrossGuard supports a wide array of cloud environments, including AWS, Azure, Google Cloud Platform, and Kubernetes, enabling users to enforce security, cost, and compliance best practices across various infrastructures. By leveraging Policy Packs, developers can bundle and apply custom policies to verify resources before deployment, ensuring adherence to organizational standards. The tool provides examples of policies such as controlling AWS costs by setting maximum spending limits, restricting Azure IoT service usage to enhance security, managing Google Cloud Platform access to prevent public exposure, and enforcing Kubernetes best practices like pinning container versions. This approach allows for more dynamic and scalable policy creation compared to traditional methods, offering the ability to integrate external data sources and apply consistent policies across different cloud providers.