You need a cookie banner if you collect data from European Union visitors. In general, only EU laws require cookies banners, which means you have a duty to show them only to your EU visitors. However, since you can’t control who visits your website and you most likely use tracking technologies (Google Analytics, Facebook Pixel, HubSpot, plugins, social media buttons), it is wise to have a cookie banner to protect yourself.
The EU first regulated this matter with the ePrivacy Directive in 2002, requiring website owners to get consent from their visitors. This is when cookie banners started appearing all over the internet. The GDPR (General Data Privacy Regulation), which came into effect in May 2018, also requires cookie banners but imposes heavier fines for those who do not comply.
You can scan your website for GDPR and ePrivacy compliance with Secure Privacy: