I have some similarities here:
They are both in the field egg group so they can breed.
If you see a Miltank or Tauros, Tauros may call Miltank and Miltank may call a Tauros.
They have the same base stat.
But I do not know if these are hints to however thay are related or not.
I'll appreciate an answer. :3
- Sincerely, Choco. ;3