Today AWS is announcing the general availability of AWS Serverless Application Model CLI (AWS SAM CLI) support for local testing of AWS Cloud Development Kit applications. AWS SAM and AWS CDK are both open-source frameworks for building applications using infrastructure as code (IaC). AWS SAM is made up of the SAM template, which is a way to describe infrastructure in an application using JSON or YAML, and SAM CLI, which is a tool to build, package, test and deploy AWS SAM applications. AWS CDK is a development framework to define your cloud application resources using familiar programming languages such as Python or Node.js.
Source:: Amazon AWS