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

https://bizzmarkblog.com/what-anchor-text-should-i-use-for-tier-2-links-pointing-to-tier-1/

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