Product Owner is an accountability defined in Scrum framework. A Product Owner is responsible for maximizing the value of a product with the help of Scrum Team. The accountabilities of a Product Owner are:

1. To set the Product Goal
2. To communicate the Product Backlogs to the Scrum Team, making them transparent and visible
3. To order the Product Backlogs to maximize the value of the product.

On the other hand, a Project Manager deals with the overall project, including responsibility assignment, project timeline, tools management, data exchange management, change management, review of work, interaction with stakeholders, risk estimation and resource management. A Project Manager is accountable to make the project successful.