Extreme Programming (XP) and Scrum are both Agile ways of working that share common values and principles. While they can be used independently, they can also complement each other in certain situations. The role of Extreme Programming in Scrum can be seen in the following ways:

1. Technical Practices: XP is known for its strong emphasis on technical practices like Test-Driven Development (TDD), Pair Programming, Continuous Integration, and Refactoring. These practices can enhance the Scrum development team’s ability to produce high-quality, maintainable code.
2. Engineering Excellence: XP promotes engineering excellence, which aligns with Scrum’s focus on delivering potentially shippable increments of work in each sprint. By applying XP practices, Scrum teams can ensure that their increments are not only functional but also technically sound.
3. Risk Mitigation: XP’s emphasis on frequent testing and feedback can help Scrum teams identify and mitigate technical risks early in the development process, ensuring a smoother sprint delivery.
4. Collaborative Culture: Both Scrum and XP foster a culture of collaboration. Pair Programming, for example, encourages close collaboration among team members, promoting knowledge sharing and cross-functional teamwork.
5. Customer-Centricity: XP’s customer-centric practices, such as User Stories and On-Site Customer, align with Scrum’s focus on delivering value to the customer. Combining these practices can lead to a stronger customer focus.
6. Continuous Improvement: XP’s principle of “Sustainable Pace” aligns with Scrum’s focus on inspecting and adapting. Teams can use XP practices to continually improve their development process.

In summary, the role of Extreme Programming in Scrum is to enhance technical excellence, facilitate collaboration, and contribute to the iterative and customer-centric approach of Scrum. Teams may choose to integrate XP practices into their Scrum process to achieve better results, particularly when working on complex software projects.