The three most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma, and melanoma. Basal cell carcinoma is the most frequent and least dangerous, characterized by pearly or waxy bumps. Squamous cell carcinoma can appear as red, scaly patches or sores that may crust or bleed. Melanoma is the most dangerous form, known for its potential to spread to other parts of the body if not detected early.