Yes, joint smoke is harmful.
Joint smoke, specifically unfiltered smoke from joints, contains harmful compounds. According to research, many of the same carcinogenic, or cancer-causing, compounds present in tobacco smoke are also found in burning marijuana. Notably, unfiltered smoke from joints contains higher concentrations of a class of chemicals called polycyclic aromatic hydrocarbons (PAHs) than does smoke from tobacco cigarettes. PAHs are known carcinogens. Therefore, inhaling joint smoke exposes individuals to cancer-causing substances, making it harmful.
