Difference between?

[Orochimaruofthesound]

hunter nin and anbu black ops

 

[SamuraiMaster99]

I'm not really sure. But maybe they are called different names depending on which village

 

[Snape Uchiha]

Hunter nin have a very specific job of finding rogue ninja and making sure their bodies don't fall into enemy hands. Anbu could have any type of S ranked assignments.

 

[phantomlord22]

hunter nin : their job is to track and kill missing nin from their country or village like what haku said in first place
black ops : ninja who work mostly as an spy or something and their missions are different from other ninjas and they must cover their faces so no one can learn about their identity.