The modelling of stars and their evolution across the HR diagram still faces outstanding challenges related to unresolved questions pertaining to the transport of chemical elements inside stars. The exquisite seismic data that are being acquired by the TESS survey, on a large number of pulsating, chemically peculiar stars, potentiates a major breakthrough in the understanding of these transport mechanisms that impact the modelling of all stars and the inference of accurate stellar fundamental properties. This workshop, organised around the project ApLAB, will focus on the exploitation of TESS data on chemically peculiar stars, aiming at setting quantitative constraints on the efficiency of the chemical mixing inside stars and furthering our understanding of the driving of these stars’ pulsations.