Tiered link building uses two levels of links to boost your site’s authority....

https://highstylife.com/how-do-i-tell-if-a-backlink-is-relevant-or-just-high-da-fluff/

Tiered link building uses two levels of links to boost your site’s authority. Tier 1 links point directly to your site and carry the most value. Tier 2 links support those Tier 1 links, making them stronger and more effective