There is a great Märklin novelty for you! It is the module wagon with light modules. It offers many great opportunities of playing.
The module wagon with light modules can make the individual details of the wagon glow. Thanks to the "Mobile Power Einheit" the wagon features 4 light functions: permanent glowing, flashing, dimming or noise-dependent glowing. (e.g. to the rhythm of your favourite music). The structure of the wagon is that of a mail wagon. Märklin Start up had a collaboration with the brand LIGHT STAX for building this wagon. The wagon and the building blocks are compatible with the building blocks of other manufacturers.
At https://www.youtube.com/watch?v=XJCG8zhKoLg you can see how to assemble the wagon.