"In my experience, product managers are the visionary of the project; they identify pain points and create something to fix them. Historically, they focus on managing the development team and communicate externally as needed. As the project manager, I come in once that vision has somewhat formed and I interpret it into concrete implementation steps. I focus on overall project scheduling, external dependencies, and the path forward. I think the key to a harmonious relationship is to start it off by defining roles specific to the project because there will likely be overlaps."