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

https://www.emergbook.win/tiered-link-building-uses-two-levels-of-backlinks-to-boost-your-site-s-1

Tiered link building uses two levels of links to boost your website’s ranking. Tier 1 links point directly to your site and carry the most weight. Tier 2 links support those Tier 1 pages, making them stronger and more trustworthy