Asymptotics is one of the most powerful mathematical tools in theoretical physics, and the modern theory of resurgent asymptotic analysis based on Ecalle's theory of resurgent trans-series yields new insights into many current problems of interest in physics and mathematics, such as quantum field theory, matrix models, holography, string theory, and quantum geometry. The 2017 KITP Program “Resurgent Asymptotics in Physics and Mathematics’’ brought together physicists and mathematicians to study these questions, and this 2020 KITP Virtual Reunion Conference highlights some of the progress that has been made since then:

• Resurgence and non-perturbative physics with applications in gauge theory, AdS/CFT, and integrable models.
• Resurgence in Chern-Simons theory.
• Picard-Lefschetz theory and novel computational methods for semiclassical analysis, lattice gauge theory, and real-time path integrals.
• Resurgence and path integrals, quantum geometry, wall crossing and topological recursion.
• Resurgent asymptotics of nonlinear differential and difference equations, exact WKB, and Stokes phases.