Insects are not always easy to identify.
Now comes the hard part. Some shield bugs, like harlequin bugs for example, feed on plants. Some are predatory and feed on soft-bodied insects like caterpillars. How do you tell which is which? A rough rule of thumb is if the beak is thicker than the bug's antennae, then it is a predator. If the beak is about the same thickness as the antennae, then it is a plant feeder.
This little guy is a predatory kind in the genus Perillus. Best to let it go about its business.