Follow-up of eROSITA and Euclid Clusters

In the near future, eROSITA and Euclid will elevate galaxy cluster and cosmology studies to an unprecedented level. Through large area surveys, they will generate huge galaxy cluster samples. Rich science will be enabled through detailed follow-up observations of systematically selected subsamples. In particular, X-ray follow-up will be crucial and XMM-Newton could play the leading role. In this talk, examples for the science enabled and possible strategies for such XMM-Newton observations will be outlined.