For junior Date Scientists, a CV consists of courses taken, education, and possibly not the most relevant work experience. Such resumes are not much different from the bulk of job seekers.
Working on a pet project is a great opportunity to improve skills. If you add the implemented pet-project to the CV, it will immediately become attractive and a topic for conversation at the interview will appear.
So what is a pet-project? Pet-project is a project that is done for yourself. It is created outside of work and is often self-interested. For example: sports, electronics, food preparation, auto, travel, medicine, etc. The project will help expand professional skills and learn new ones that will be useful in work.
Here are some ideas for projects in Data Science that you can get started with: