A systematic mapping protocol is a method for conducting a literature review in a rigorous and transparent way. It aims to provide an overview of the current state of research on a specific topic, identify gaps and opportunities, and guide future work. In this document, we present a systematic mapping protocol for investigating the role of the UX designer in the software development process. We define the research questions, scope, sources, search strategy, selection criteria, data extraction, and analysis methods that we will use to conduct the mapping study. Our goal is to understand how the UX designers collaborate with other stakeholders, what methods and tools they use, what challenges they face, and what outcomes they achieve in different contexts and domains.