As a manager in an organization, no matter how small, you'll find a lot of your work revolves around collaborating with internal and external stakeholders. It is impossible for you to individually manage all stakeholders that are relevant to your team.
That's where stakeholder mapping comes in. An effective manager will map different stakeholders to their team members based on how work is distributed in the team. For example, a product marketing lead may map a specific product manager to one of their product marketing managers. Now this may sound self evident to you, shouldn't a person be mapped to whoever they work with?
Yes, however, you may find that your team partners with a number of stakeholders on an adhoc basis and unless you explicitly map people in your team to them, the relationships and thus the meetings that are required will always land on your plate. A strategy that pays off in the long run is to proactively map counterparts across the organization to people in your team e.g. if customer research and your team collaborate ~once a quarter, make a team member who is interested in research on your team the stakeholder map in your team.