Tiered link building uses two levels of backlinks to boost your site’s ranking....

https://www.coast-bookmarks.win/tiered-link-building-helps-boost-your-website-s-authority-by-creating-different

Tiered link building uses two levels of backlinks to boost your site’s ranking. Tier 1 links point directly to your main site, giving it strong, direct value. Tier 2 links support those Tier 1 links, making them stronger and more effective