Ask HN: Most important issues for compsci students to learn about and solve?

Question inspired by a new undergrad econ "textbook" that identifies inequality as one of the most important problems in economics to understand and study today. Discussed here: https://news.ycombinator.com/item?id=15282766

What are some equivalent problems in computer science, and if you were setting out to write a textbook, what would you want students today to learn about and solve?