LDAP vs OAuth2: What are the differences?

What is LDAP? A lightweight directory access protocol. It is a mature, flexible, and well supported standards-based mechanism for interacting with directory servers. It’s often used for authentication and storing information about users, groups, and applications, but an LDAP directory server is a fairly general-purpose data store and can be used in a wide variety of applications.

What is OAuth2? An open standard for access delegation. It is an authorization framework that enables a third-party application to obtain limited access to an HTTP service, either on behalf of a resource owner by orchestrating an approval interaction between the resource owner and the HTTP service, or by allowing the third-party application to obtain access on its own behalf.

LDAP and OAuth2 can be primarily classified as "User Management and Authentication" tools.