Many of my acquaintances use Slack to communicate in teams. Should you also belong to it and also be iOS users, then you may soon be happy about a dark mode because this has landed in the current beta version of Slack.
If you already use the beta, then you can go through a hint on the three points in the upper right corner in the settings and there activate the toggle for the Dark Mode. If you still want to sign up for the beta test, you can do this through this website.
Gradually, many app developers give their users a dark mode in the hand, depending on the taste, this time is dark gray or completely black. All expect a true system-wide dark fashion for the upcoming release of iOS 13. Up to now, in the settings, you can only use the accessibility controls to select an intelligent mode for a color reversal to banish the white from the system. That does not always look nice.
By the time of the WWDC in June, we will be a little smarter.