Statues that exist independent of any architectural frame or setting and that viewers can walk around are called in the subjects project from the background but remain part of it.

Statues that exist independent of any architectural frame or setting and that viewers can walk around are called Free-standing Sculptures. In Relief Sculptures, the subjects project from the background but remain part of it.

Explanation:

Free-standing sculptures are those "full" sculptures which can be observed at 360°, all around. A very famous example could be Michelangelo's David.

Relief sculptures are the ones that emerge, more (high relief) or less (low relief), from a background, but the observer can only see up to 3/4 of the image.