The human microbiome is the collective genomes of microorganisms which reside on or within human tissues and biofluids such as the skin, oral cavity, and gastrointestinal tracts. In recent years, various types of human microbiomes have been sequenced, and a huge amount of data has been accumulated. By exposing metadata of microbiome data as RDF, it is expected to further cooperation among microbiome data and as a result, it will lead to more advanced human microbiome analysis. In order to improve the interoperability of RDF datasets, it is important to use common vocabularies and RDF models. This project was initiated by SPARQLthon 80 participants, who are involved in RDFization of microbiome data. The purpose is to define the minimum requirements of metadata of human microbiome data, which will include RDF schema, ontologies, and vocabularies to be used.