Hello gossipgroni,
Thanks for reaching out to the Apple Support Communities! That's a great question you have about what will happen if you cancel your Apple Music subscription. Once your Apple Music subscription is canceled you will lose access to the playlists you created and any music you've downloaded. Also, your music and playlists would not return if you decide to sign up for Apple Music again in the future. However, you will have access to it until the day your subscription officially ends and your purchased music would not be affected.
If keeping your subscription active isn't possible for you right now, we recommend writing down the songs in your playlists or taking screenshots of the playlists so you can set them up again the same way once you're subscribed again. Here's how to take a screenshot: Take a screenshot on your iPhone.
Thanks again for the question and take care!