If you own a website, you will need to make sure it complies with the law, and this usually means making some changes.
If you don’t comply you risk enforcement action from regulators, which in the UK means The Information Commissioners’ Office (ICO). In exceptional cases this can mean a fine.
However, non-compliance could also have other, perhaps more serious consequences than enforcement. There is plenty of evidence that consumers avoid engaging with websites where they believe their privacy is at risk, and there is a general low level of trust about web tracking by the use of cookies.