You can also add the subscribers directly to your MailChimp’s list.

Go to WooCommerce -> Coming Soon Settings -> MailChimp and provide your Mailchimp API key here and save the settings.

Now when you will go to the product edit screen and enable the Email Subscription, you will see another menu to choose your MailChimp list. Choose a list here and all subscribers will also auto-subscribe to the MailChimp’s list as well.