How to even this brick/concrete wall?

You will need to build a wall in front of it with wood framing, that way you can add plastic and insulation over it then add drywall. You can also have a mason come out and reface it for you but that would be costly and you wouldn't have any insulation so it's up to you. When framing for a basement you need to use floating walls which means you will need to use a bottom plate and spikes holding the bottom of the wall to it so it can move without cracking the drywall. Most codes require it so look into what your areas building department suggest.