Most objects within improveit 360 allow all Users to create and edit List Views for that object. However, the Campaign Members object has a limitation.
Only Salesforce licenses (not Salesforce Platform licenses) can Create or Edit List Views for the Campaign Members object. This means, only System Administrator Users can Create or Edit Campaign Member List Views.
If you are not the System Administrator for your organization, contact your Admin User and ask them to create the List Views you need to see on the Campaign Members Tab.