The Research Pod in Machine Learning brings together researchers from theoretical computer science, mathematics, statistics, electrical engineering, and economics to develop the theoretical foundations of machine learning and data science. Led by Simons Institute Associate Director Peter Bartlett, this pod is partially funded by a $12.5 million award made under the National Science Foundation's program on Transdisciplinary Research in Principles of Data Science to establish the Foundations of Data Science Institute (FODSI). This institute, a collaboration between UC Berkeley and MIT, partnering with Boston, Northeastern, Harvard and Howard universities, as well as Bryn Mawr College, aims to improve our understanding of critical issues in data science, including modeling, statistical inference, computational efficiency, and societal impacts. NSF, together with the Simons Foundation, is also supporting the activities of the pod through the Collaboration on the Theoretical Foundations of Deep Learning. This is a collaboration of 11 PIs from eight institutions around the world that aims to understand the mathematical mechanisms that underpin the practical success of deep learning. The Simons Institute will act as the convening center for many of these activities, hosting public events such as summer schools, research workshops, and other collaborative research opportunities.