GDPR became enforceable on May 25, 2018 in the European Union. The GDPR mandates that each individual has access and control over the use of its data, while the blockchain relies on the immutability of data.
These two concepts seem in direct conflict with each other. Vitalik expressed his disappointment in May of this year when PICOPS (Parity ICO Passport Service) had to close doors because of the GDPR.
Since then I am surprised that this topic seems not getting a lot of attention in the community although it seems on first side that these two concepts are on a collision course.