Both the English Communication and English Business Courses aim to improve your communication skills, but the areas of focus are different.
The English Communication Course focuses on communication skills for everyday situations. This includes topics about friends, hobbies, health, education, food and drink, shopping, and places where you live or spend time. The lessons cover a broad spectrum of skill objectives from the A1-C2 CEFR ranges. This would be ideal if you plan to take a certification exam.
The English Business Course will help you improve your professional skills for the workplace. This course includes topics about teamwork, meetings, presentations, workplace correspondence, networking, customer service and talking about facts or figures. The lessons cover a targeted spectrum of skill objectives starting from the B1 CEFR range that apply directly to the English Business Course. If you plan to take a certification exam, you should consider taking the English Communication Course as well.