The new edition of MassMailer captures all your outreach emails into an object called 'MassMailer Outreach' which holds the information about your email outreach such as template, sender, recipient, email statistics, bcc information, schedule information, subscription group, IP pool, etc.

If you send an email via the 'MassMailer Outreach Wizard' directly or from a Salesforce record, or a Salesforce List View, or through a Process Builder, or via Salesforce Campaign it all gets stored in the 'MassMailer Outreach' Object.

If you send an email from the Salesforce Campaign, you will a related list on the 'Salesforce Campaign' called 'MassMailer Outreaches'. That way you can link up these two objects to report on any more information about the email sent via the campaign.