HubSpot Sales Professional is able to track link clicks, by wrapping a link's destination address with a tracking URL. This tracking will be applied to any hyperlinked text in an email. Tracking will only occur on hyperlinked text, and not raw URLs. For example:
Tracking will be applied:
Tracking will not be applied:
Although these links have the same destination, since the second link is a raw URL, tracking will not be applied.
Note: As it turns out, it is not currently possible to prevent link tracking in Apple Mail. Raw URLs and hyperlinked text will both be tracked.