It’s not just what it looks like and feels like, Design is how it works.”
Steve Jobs
Integrating UX design within Agile is an important topic and several good articles and guides mentioning different approaches are available on internet. Many individuals and organizations are taking guidance from them.
Some of them state that it is better to run a separate design sprint along with development sprint. And this design sprint should go ahead of development sprint.
In my professional experience, we often designed a backlog feature one sprint ahead of the development team. This helps the dev team to have an approved design feature for their development to run smoothly and on time.
Jamie Goldsman 