Hi @a3093,
SSO is currently on the Roadmap of Checkmk. You can have a look here → The Checkmk Roadmap
We plan to support SAML for Single Sign-On.
Although you can already use LDAP or integrate Kerberos Authentication but Kerberos is not officially supported by Checkmk.
A single sign-on to the GUI of Checkmk with Kerberos is not officially supported by Checkmk, but you can easily set it up yourself.
You can read more about Kerberos here → Single sign-on with Kerberos
More info on LDAP can be found here → User management with LDAP/Active Directory
Hope this helps. 
Greetings Norm