The CIO basically is the boss of everything that involves technology. There is a good explanation on wikipedia. A project leader normally leads a single project. That could be, for example, building the infrastructure and software to open up a new logistics center. Or maybe replacing all the old components of a medical software in a specific hospital. Or whatever else business wants done to generate money.
To become a project leader, you should probably know the business the project is in and you should have experience leading projects. Ok, that is hard to come by without being a project leader, so most people get in in very small projects or as assistants. Most companies have multiple projects and project leaders, so one can come from the outside or promoted internally.
CIO is a different level. The so called C-level (everything title starting with a C for "Chief") is quite unique. You only have one of each in a company, there can be only one chief per field. You can certainly rise through the ranks, but that would mean the old CIO needs to step off or be promoted. Both is unlikely. It's more likely you don't want to wait for that and apply for this position outside your own company, so CIOs tend to come from the outside. There is no set path to become CIO, from the CIOs I have seen, the best have been developers, managers and software architects before. The job of a CIO needs a lot of real world experience. Something you gain either because you open up a startup and give the jobtitle to yourself, or you have 20+ years experience in the field.
As always, exceptions apply. Neither project lead nor CIO are jobs clearly defined by a govermnent body (or the IHK in Germany). You don't need to have a certificate. If you wanted, you could found a company and give the title of CIO to your kitten.
Some people (me included) avoid management positions. You will find that pretty often in the IT field. Most people go into the field because they like it. They like opening a compiler and coding. Thinking about designs and making them come to live. Once you manage stuff, being it people, a project or a whole company, that time is over. As a project lead or CIO, your day will be meetings. Meetings , meetings, meetings. The time in between will be spent reading the meeting minutes and preparing for the next. The most technical you will get is opening Outlook to check your next meeting and reading email. As a project lead or CIO, you will never open a compiler, use source control or actually see the product. That's three levels beneath you. You will have a meeting to tell the managers what you want done. The managers in turn will tell the architects what needs to be done. The achitects will tell the developers what to do in practice. If you are lucky, you will get an email how it's going. But actually reading and understanding it will be something of a luxury thing while you are on your way to your next meeting.
