Opens and links are separate purposes: the company switches each on separately, and each needs its own consent from the recipient, so a person can be tracked for links but not for opens. A consent comes from the recipient’s own act, for example the HawkOpen consent form behind a link your company passes on itself, or is recorded by the owner or an administrator from consents your company collected. Links that do not start with https, such as links to an email address or plain http links, stay as they are and are not tracked.
Each click gets a category, such as security scanner, link preview or human, with the rule codes behind it. A single click does not send a notification; on Business an email click alert can tell you about the first click that is not classified as a machine. A click is often a stronger signal than an open, but company filters also click links, so read the category before drawing conclusions.