NTLM is still used for computers that are members of a workgroup as well as local authentication. In an Active Directory domain environment, however, Kerberos authentication is preferable. For backward compatibility reasons, Microsoft still supports NTLM. Since a non-Microsoft or Microsoft application might still use NTLM.
From Windows Server 2003, Kerberos has been suggested rather than NTLM as it’s a stronger authentication protocol which uses mutual authentication rather than the NTLM challenge/response method.
However, with group policy we can disable the older NTLM and only allow Kerberos, this is known as NTLM blocking. Before doing this however, you should check and ensure that both Microsoft and third- party applications in your network do not require NTLM authentication before proceeding.