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

https://high-wiki.win/index.php/What_is_Tiered_Link_Building_in_SEO_and_Is_It_Safe%3F

Tiered link building uses two levels of backlinks to boost your site’s authority. Tier 1 links point directly to your site, while Tier 2 links support those Tier 1 backlinks