There are many schools of Buddhism, and tons of different concepts that are off in Buddhism. I’ll just mention a few:

• Meditation as a path to liberation
• That there is a path to liberation
• That someone could be enlightened / liberated
• A teacher / guru / lama / lineage
• Deity worship
• Practicing anything such as compassion or loving-kindness with an intention of it having any effect
• The idea of training the mind / controlling the thoughts
• I recently listened to a long talk about no-self by a buddhist scholar. He clearly had no idea what he was talking about and seemed to believe that there is someone who could somehow achieve no-self