Today, digital transformation remains a key strategic objective for most companies. Through these processes, they seek to stay ahead in a constantly changing industrial environment and improve their competitiveness in markets characterized by high uncertainty. In this context, Lean emerges as one of the most widely used business management methodologies because it seeks the maximum efficiency of the company by eliminating elements that represent an additional cost and do not add value to the product or service. However, despite various methodological proposals that guide digital transformation processes, challenges persist in implementing the necessary cultural changes. Therefore, it is essential to remember that the main focus of any digital transformation initiative must always be on people. In this context, user experience (UX) emerges as a critical element in the success of digital transformation initiatives, as it directly impacts customer satisfaction and the adoption of digital technologies. Driven by the need to explore the development of these processes, we have conducted a comprehensive review of the literature related to digital transformation, UX, and Lean. Our main goal is to understand the challenges inherent in improving UX in the context of digital transformation using Lean as a methodology. Following analyzing the selected primary studies, we have identified relevant Lean principles and practices to be considered in digital transformation processes. In addition, we identified the main challenges in their integration and the opportunities that this integration offers. The evidence gathered indicates that digital transformation will continue to be a priority for companies pursuing Industry 4.0. In future work, we plan to conduct a tertiary study to synthesize the knowledge captured in many existing systematic reviews.