Ze/Hir is a gender netural pronoun that mostly get used by people which is male alligned people while some female alligned people (Like me) uses it. Ze is a replacement for He/She/It or They. Ze can be used with Hir or Zir.
B: Is that her dress?
A: No, it is hir dress.
B: Isn't her pronouns are She/Her?
A: No, ze uses Ze/Hir.