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

https://alpha-wiki.win/index.php/What%E2%80%99s_a_Realistic_Outreach_Workflow_for_a_Solo_Marketer%3F

Tiered link building uses two levels of backlinks to boost your site’s ranking. Tier 1 links point directly to your site and hold the most value. Tier 2 links support Tier 1, helping them pass more authority