Two similar effects can be to add a Title with a Shape, say an oval, that has only a Stroke, and no Fill, and place it on an upper Video Track. This can be Keyframed to "follow" the subject, with the fixed Effect>Motion>Position (and also Scale, if necessary), to draw attention to the subject.
Similar to that would be a Title with an "arrow" pointing out the subject. I like using a Webding, or Winding font of an arrowhead. Again, this arrow can be Keyframed to follow the subject with that fixed Effect>Motion>Position. Depending on the subject and their motion, the fixed Effect>Rotation might also be Keyframed.
Here is an "oval:"
Here is an Arrow:
Here is an Adobe Article on Track Matte Keying in PrPro CS5. Though one might not have that particular program version, the general concepts are pretty much the same.
Hope that this helps.
PS - cannot recall if I linked to Curt Wrigley's excellent tutorials on using Track Matte Keying, but he has taken down his wonderful site.
There might need to be a little interpolation for other versions of PrPro, but it should be slight, as few changes, that will affect the Track Matte Keying were introduced. Might be a name change, or two, but nothing major.
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