Traditional marketing aims to promote a business's entire product offering and elevate the brand. While product marketing does work with marketing teams to execute product releases and craft go-to-market messaging, a product marketer's focus is narrower than a marketing manager's. A product marketer is focused on selling or creating interest around one specific product, whereas marketing teams often promote a company's entire suite of product offerings.
You'll also often find that it is the product management team that is responsible for truly understanding their buyers, and the roles they play within the buying process. The product management team spends a lot of their time speaking to customers, understanding their pain points and engaging with them on the products they use. With information like this, the product management team can take these insights to the marketing team in order to help their marketing efforts become a lot more effective.