link building is a part of seo you and without it you can not optimize your websites.
thanks and regards

Link building assumes significance from an SEO point of view. It is true that SEO refers to the strategy of linking other websites to your own.

Link building is back bone of your website.

The process of establishing relevant, inbound links to your website which help your website achieve higher ranking with the major search engines and drive targeted traffic to your site.

Link building can help your site get more traffic and maybe higher PR.