  Understanding and simulating how a quantum system interacts and exchanges
information or energy with its surroundings is a ubiquitous problem, one which
must be carefully addressed in order to establish a coherent framework to
describe the dynamics and thermodynamics of quantum systems. Significant effort
has been invested in developing various methods for tackling this issue and in
this Perspective we focus on one such technique, namely collision models, which
have emerged as a remarkably flexible approach. We discuss their application to
understanding non-Markovian dynamics and to studying the thermodynamics of
quantum systems, two areas in which collision models have proven to be
particularly insightful. Their simple structure endows them with extremely
broad applicability which has spurred their recent experimental demonstrations.
By focusing on these areas, our aim is to provide a succinct entry point to
this remarkable framework.
