Read more about using filters here.

The following filters are provided for workflows using MailChimp Webhook as trigger:

Filter Description
MailChimp List Checks if the MailChimp list (single value) is specified as comparison value. Use this to make sure the MailChimp Webhook is notifying about the MailChimp list you expect.
MailChimp Email Checks if the email address (string) provided with the MailChimp Webhook matches with the comparison value using the selected operator. Use this to exclude certain addresses/domains.
MailChimp update type Checks the update type that the MailChimp Webhook notified about.