Import users from LDAP
As the comment noted this question would benefit from much more detail.

There are 2 very broad scenarios here;


Loading LDAP user attributes for use and reference within Drupal (probably user entities) users that exist.
Linking LDAP users to Drupal in an ongoing fashion including some form of authentication requirement.


In the first case you won't likely be dealing with LDAP user credentials (which is good) and greatly simplifies the implementation.  This is a good example; on Drupal.org using LDAP feeds.

In the second case LDAP feeds is probably not the best or only module you'll need.  This d.o article covers some ground but there are important gaps, but also some good linked resources in that section that could be of great help to you depending on your needs.

There are a plethora of variants on these cases.  One time vs ongoing, update bi-directional or with one resource overwriting the other as authoritative, updating non-user entities and keeping them in reference to users, and many more.  This split is designed to identify the most likely cases from the question you asked.

If this is one-time, an option (not ideal) may be to bring the users into an interim D7 instance and then migrate them to D8.  This could be done repeatedly but would require a standing D7 instance to maintain.  I'd only suggest this until the D8 LDAP feeds project is further along.  It could give you time to dig in and contribute as well. ;)

Giving this further thought and since the module isn't fully ported, this could be done with a server cron, a little scripting and a docker D7 instance.  A nightly docker spin up, pull from LDAP into D7 and migrate users to D8.  It's far from a good solution.  But it sounds like your need is immediate and this would work.  If time isn't a factor either porting the module yourself or paying someone to do it is the best path.

I'm happy to amend or expand this answer as needed based on additional information added in your question.