First cosmological results from the eROSITA all-sky survey have been revealed earlier this year. They demonstrate the constraining power of galaxy clusters in late-time cosmology experiments, in particular in the domain of dark energy. I will briefly recall the motivation for the high-energy space mission eROSITA in the context of X-ray cluster cosmology. I will then discuss first cosmological results obtained through analysing the abundance of galaxy clusters, putting special emphasis on delicate selection effects and mass calibration. Finally I will present some prospects for the future exploitation of the galaxy cluster content of the eROSITA all-sky survey.
