Can we Write Add-on plugin for an existing plugin from another developer

I’m in need of a plugin with a list of features , but a plugin I found developed by another developer meets only few features.
In that case , can I develop a add-on plugin with my requirements & release it as “Add-on for XYZ plugin” ?
If so should I have to ask the other developer’s permission to develop & release such add-ons ?

Hope my question is clear & understandable.