How does sunburn compare to other burns and scalds?

Is “sunburn” only a metaphorical “burn” or is it similar to a burn* from thermal conduction as far as the skin is concerned? What about chemical burns, etc.?

Also, sunburn is well-known for causing/contributing to skin cancer. Are other burns just as dangerous in this respect?

it’s a radiation burn. UVB and UVC are ionizing radiation.