Some data is so sensitive that processing it is, in principle, prohibited (GDPR, article 9.1):
Racial or ethnic origin, political opinions, religious or philosophical beliefs.
Trade union membership.
Genetic data and biometric data that identify a person (for example, fingerprints).
Health data, physical or mental (article 4.15).
Sex life or sexual orientation.
When it can be processed
Only in the cases of article 9.2: for example, with explicit consent or when needed to meet obligations under
employment and social security law.
In practiceSaying in the team chat that a colleague «is off sick with depression» discloses
health data. Sick leave is handled by whoever has to handle it, discreetly.