The ELLIS Unit Saarbrücken brings together six PIs from four research institutions of Saarland Informatics Campus (SIC). It comprises the Max Planck Institute of Informatics (MPI-INF), the Max Planck Institute of Software Systems (MPI-SWS), Saarland University (UdS), and the CISPA Helmholtz Center for Information Security (CISPA). The PIs have agreed to jointly work on both the foundations for enhanced functionalities of Artiﬁcial Intelligence and Machine Learning (AIML) systems and the pressing needs for security, privacy, and trustworthiness that arise from the widespread use of AIML systems. In the future, these systems will capture reality through a multitude of sensors, interact with humans, derive knowledge, and inﬂuence our lives. They will make autonomous decisions and enable enhanced functionalities, e.g., for personalized assistants, immersive multi-person platforms, and autonomous systems. This ELLIS Unit will research the foundational algorithmic solutions needed to enable systems capable of such new functionalities and design new algorithms for high trustworthiness, controllability, and explainability.