MongoDB Performance Tuning and Monitoring with MMS` involves using the MongoDB Management Service (MMS) to optimize and monitor performance in MongoDB deployments. The service is used by Daniel Coupal, a MongoDB Technical Services Engineer, who shares his expertise on how to identify key metrics for improvement. Through real-world examples, Daniel demonstrates the value of MMS in diagnosing and debugging performance issues, making it easier for users to troubleshoot their own issues. With monitoring being completely free, users can try out MMS and gain insights into their MongoDB performance without any cost.