Schema.org is a specification for describing metadata in HTML, JSON, etc.
It is generally called structured data, etc., and has recently become widely recognized as a method for dealing with rich snippets in search engines.
It was originally designed based on the concept of the Semantic Web , but it was not widely used because it had few advantages.
However, since search engines such as Google have prepared rich snippets etc. as a merit, they will become popular.
For the search engine side, it is a great merit that the accuracy and speed of content understanding are improved, so they have come to be shared by Schema.org in line with each company.