Just a quick brainstorm when checking a design wireframe for potential accessibility issues, finding low level problems that may be solved way earlier than we may think. Maybe even before designer became a designer and before developer became a developer?
Common effort, interdisciplinary competence and early dialog can be the only best practice for assuring the accessibility of the final product. If we leave that team members live in their own roles then we are almost surely to fail and get into situations where the issues on the end prevent launching accessible products and flood the team with issues. Cooperation and dialog are key!