Should “cancel” be a button or a link?

Which one is UX best practice?

Cancel as a link vs. Cancel as a button

A common type of dialogue that is often presented when interacting with a web app, is the “cancel” option. Usually when the user is filling out a form, or manipulating data (e.g. inside a side panel, detail page or modal view). One would typically see it next to a primary action, presented as a link. More and more however, this cancel option is…