Backlinks are plain or contextual links that point from another website to your web pages, they can be "dofollow"(recommeded) or "nofillow"(notrecommended), also can be known as “inbound links”, “hyperlinks”, “incoming links”, or just “links”, Giving your web page more trust, authority and leads.

Google and other search engines perceive Backlinks as endorsements for a page. Yet, certain links hold greater weight and credibility based on the linking site's quality and context. Typically, pages with a robust backlink portfolio, comprising superior links, enjoy higher ranking in organic search results other competitors.

OBVIOUSLY, Building backlinks are essential for search engine trust, in human context this can be related to you being famous, celebrities are most likely trusted and reliable in every human check text, the more people know you, the more trusted you become to others as well.