Schema markup is not a ranking factor, however it can boost SEO results. Website schema markup helps search engines understand the content on your pages and provides richer results to saturate the search landscape and boost visibility. Adding schema tags to your website code favors Google Algorithm updates like BERT.
Schema gives search engine bots the context of the website content and in turn, the content is more likely to be featured as a rich result on SERPs. This boosts the impressions of the website content on SERPs and possibly the click through rate (CTR) as the answer to a query is prominently displayed. This also gives users answers to their queries without having to click.