Both expertise areas, UX and Marketing, are focussed on the same thing: getting to know the (potential) clients, the users of the products and services, and making their journey as valuable as possible by understanding them, interacting and cocreating with them, and making this relationship sustainable.
I remember that I discussed with one of my dear Dutch UX friends the fact that “UX” for some clients still is “making wireframes”. They think that experts that work in this field are visual designers that focus on interface design. Next to the fact that interface design is important to improve the user experience of a digital service, UX experts are not necessarily visual designers. Quite the contrary! Especially strategic UX experts combine data with (visual) experience aspects; being a customer data/behaviour analist and using those data to map the whole customer journey, and defining and engineering (digital) services to optimise that journey. All of that based on clear business goals and KPIs, not for the sake of pretty design.