Structured data markup, or schema, helps search engines understand the content on a website and can improve local SEO for San Francisco businesses by enabling rich search results. By implementing local business schema, such as organization, address, phone number, and business hours, businesses can enhance their visibility in search engine results and make it easier for customers to find essential information directly on the search results page. Structured data can also increase the chances of appearing in Google’s local pack, which is valuable for attracting both residents and tourists in San Francisco.