Our crisis-riddled world exposes the need for extended forms of cross-boundary knowledge integration when solving complex problems. Complex problems are characterized by the multilayeredness, interdependent coupling- and feedback mechanisms, and adaptiveness of the underlying systems. These problems tend to be ill-defined, ambiguous, and open-ended, and so the argument is made that one-sided/one-dimensional, disciplinary, and purely science-based views are inadequate to tackle complex real-world problems. Furthermore, difficulties in understanding a given problem can lead to a loss of trust in science. Dealing with complex real-world problems such as poly-crises and systemic risks thus calls for the integration of various perspectives and bodies of knowledge of various scientific disciplines and fields of practice, experiences, and future-oriented thinking. This chapter outlines why transdisciplinarity as mutual learning between science and practice, holds great promise for tackling societally relevant complex real-world problems. It can also be of great benefit in assessing the future development path of such coupled systems, including possible intervention scenarios, and their interaction with a dynamically changing environment. Last but not least, this approach can help to restore trust in science, which is dependent on a trustful communication and learning environment. I propose that transdisciplinarity-based thinking, communicating, collaborating, and mutual learning may help to (1) better deal with the complex challenges society faces, (2) overcome fallacies in our understanding of complexity, and (3) increase trust in science, thus ultimately contributing to a better world.