Conact Retargetting from outside mautic emails

Your software
My Mautic version is: 2.15.1
My PHP version is: 5.6.40

Your problem
My problem is: Contact Tracking from outside emails

I am using Mautic as CRM and even used for marketing automation but as emails were not going in inbox(was going in Updates tab) we switched email sending to Lemlist. But we are still using mautic as CRM. My question is that if we want to show Dynamic Content to users based on activity then how I can do it using such combination?