Since Samba 4.4, Samba has required Winbind to be running for WINS resolution (https://wiki.samba.org/index.php/Samba_4.4_Features_added/changed#WINS_nsswitch_module). But, since Samba 4.4, I can't get WINS resolution to work no matter what I do, whether the Winbind dæmon is running or not.
With my /etc/nsswitch.conf hosts entry listing "hosts: files dns wins" (and sometimes I'll omit the "dns" part to test WINS resolution), I can revert to Samba 4.2 and WINS resolution will succeed. But, once I upgrade to Samba 4.4 or later (4.5, 4.6), nothing I do will result in the same name resolution test succeeding, even after enabling the Winbind dæmon.
~> nmblookup hostname
~> ping hostname
ping: unknown host hostname