Rather than managing one project they are responsible for managing multiple projects while simultaneously working to improve their organization’s processes, performance, and ensuring that their customers and key stakeholders are satisfied.
Product managers are concerned with strategy and delivery whereas program managers are mainly concerned with delivery.
One interesting thing to note is that the role “program manager” is used to describe product managers in some organizations. For example program managers at Microsoft are more akin to product managers than project managers.
When applying for any product management role make sure you read the job description carefully.