Was the ECHR affected by Brexit?
No – although their names sound similar, the Council of Europe is completely separate from the European Union (EU). While the EU is a political and economic union that largely deals with issues like trade agreements, migration and working conditions, the ECHR is about fundamental rights like the right to freedom of thought and expression and the right to free elections.
The court that deals with matters related to the EU is called the Court of Justice of the European Union. The court that deals with matters related to the ECHR is called the European Court of Human Rights. Again, these courts are not related even though their names sound similar.
Brexit was about leaving the EU. It did not impact the Council of Europe, so the UK still has to follow the ECHR and judgments from the European Court of Human Rights.