Tiered link building uses two levels of links to boost your website’s rankings....

https://www.acid-bookmarks.win/this-article-breaks-down-tiered-link-building-into-simple-steps-it-explains

Tiered link building uses two levels of links to boost your website’s rankings. Tier 1 links point directly to your site and should be high quality. Tier 2 links support those Tier 1 links, helping them rank better in search results