Unfortunately, for Minecraft Java Edition, there are no skins that will automatically incorporate a cape. However, in Bedrock Edition, there are some skin packs that come with capes included.

Skins and capes are pretty common in Minecraft. Most gamers don't use the standard Alex or Steve skin that the game provides.

Minecraft Steve has been added to Super Smash Bros Ultimate, and there's now a mod that lets you make use of your Java skins.