  Mobility as a Service (MaaS) is revolutionizing the transportation industry
by offering convenient, efficient and integrated transportation solutions.
However, the extensive use of user data as well as the integration of multiple
service providers raises significant privacy concerns. The objective of this
survey paper is to provide a comprehensive analysis of the current state of
data privacy in MaaS, in particular by discussing the associated challenges,
existing solutions as well as potential future directions to ensure user
privacy while maintaining the benefits of MaaS systems for society.
