Special category data is data considered to be more sensitive and therefore requiring extra protection. This includes data regarding racial or ethnic origin, political opinions, religious or philosophical beliefs, trade union membership, genetic data, biometric data (when used for ID purposes), health, sex life and sexual orientation.
If you process any of these types of special category data then you should read this new guidance carefully and make sure you are applying the GDPR requirements to ensure protection of this special data.
The guidance sets out more detail about what constitutes these different kinds of data, what the GDPR and Data Protection Act 2018 say as well as detail about the conditions for processing (which are required for special category data along with your lawful basis for processing). It also sets out the documentary requirements (and provides a template) if you are relying on the public interest condition.