Hiding:
hiding objects in the drawing enables you to hide them from view, but they are still there
this is done by selecting objects and then clicking on the Hide toolbar button, located on the Home tab of the Ribbon
Isolating:
isolating objects in a drawing enables you to isolate them from all other object interactions, including selection and editing operations. This is typically used for complex drawings with many overlapping or intersecting objects.
this is done by selecting an object and then clicking on the Isolate toolbar button, located on the Home tab of the Ribbon