Sequelize is a promise-based Node.js ORM tool that enables developers to interact with databases using JavaScript instead of SQL, and it now supports YugabyteDB through the `sequelize-yugabytedb` package. YugabyteDB is a distributed SQL database for transactional applications that combines enterprise-grade relational database capabilities with horizontal scalability and resilience, making it suitable for scale-out OLTP workloads with low query latency and extreme resilience against failures. To use Sequelize with YugabyteDB, developers need to start by setting up a local cluster on their machine, create a Node.js project, install the `sequelize-yugabytedb` package, define models using the `sequelize.define()` function, and then sync the table schema and insert data into it. Once the code is executed, the results can be verified by looking at the changes inside the database.