If you have clicked subscribe but the mod does not appear in the launcher, try the following steps before asking about it! I am not a spokesman for PDX or Valve and do not know anything beyond the following suggestions:

1. Load the game all the way to the main menu, exit, then check the launcher again.
2. Restart Steam completely.
3. If the above do not work, download manually at the link in the description.
4. Mac and PC Users, complete step three and extract the contents to:
"/Documents/Paradox Interactive/Europa Universalis IV/mod"