Identity management
Identity management is a broad concept that deals with many different aspects and involves interaction with many different systems.
This concept is indeed related to identifying a user (that is, who is asking for a particular resource or functionality) and checking the associated permissions (whether they are allowed to do so and so, or not). So, it's easy to see how this is a core concept, common in many applications and many components inside the application. If we have different functionalities provided by different components (as in a microservices application), then obviously each of them will need to perform the same kind of checks, to be sure about the user's identity and act accordingly.
However, having an ad hoc identity management infrastructure for each application can be considered an antipattern, especially in a complex enterprise environment, since each application (or component) has the same goal of identifying the user and its permissions...