Yes, the number of internal links to a page is a ranking signal, according to the original PageRank paper from Google’s Sergey Brin and Lawrence Page.

In case you were wondering, as of 2018 Google still uses PageRank:

DYK that after 18 years we're still using PageRank (and 100s of other signals) in ranking?

Wanna know how it works?https://t.co/CfOlxGauGF pic.twitter.com/3YJeNbXLml

— Gary "鯨理／경리" Illyes (@methode) February 9, 2017

For example, if an ecommerce page is part of the category taxonomy, and that page is included in the global navigation of the website, then the pages gets significantly more internal PageRank than pages not linked from the global navigation. This behaviour is based on how PageRank was designed. If you move this page from the category taxonomy to a filter, its rankings will drop.

Keep in mind that PageRanks flows in complex ways (i.e. footer links will pass less PageRank, or contextual links pass more PageRank than non-contextual links). Also, external links will influence how internal PageRank flows as well.