Can you post a photo? Answer yourself, to give more details, of what you want.
The sky is the limit depending on your style. Please post a photo and describe if you want to change the "character" with a certain style (traditional, loft look, mid century modern, industrial, etc.).
Or do you just want to recover the treads?
Or are you interested in changing out the pitch of the steps?
I’ve seen some lovely projects where they applied wallpaper or contact paper to the face of the step. Then paint the tread or refinish the wood.