CircleCI has introduced a feature called CircleCI Runner, which extends the platform's capabilities by allowing developers to run workloads in diverse environments, addressing specific needs such as compliance in highly regulated industries or building on non-cloud hardware. The feature enables users to meet stringent security and compliance requirements and is particularly beneficial for those working on embedded systems or IoT. A detailed guide is provided on setting up CircleCI Runner, including creating necessary accounts, configuring environments using Terraform, and provisioning runner nodes on platforms like DigitalOcean. The process involves creating namespaces, resource classes, and runner tokens, alongside automating node provisioning through scripts. The guide also covers defining runner jobs in CI/CD pipelines and offers tips on software installation, security, patch management, and understanding runner limitations to ensure effective and secure operation.