curl --request GET \
  --url https://discord.com/api/v10/guilds/{guild_id}/bans/{user_id} \
  --header 'Authorization: <api-key>'

{
  "user": {
    "id": "<string>",
    "username": "<string>",
    "avatar": "<string>",
    "discriminator": "<string>",
    "public_flags": 123,
    "flags": 0,
    "global_name": "<string>",
    "primary_guild": "<unknown>",
    "bot": true,
    "system": true,
    "banner": "<string>",
    "accent_color": 123,
    "avatar_decoration_data": "<unknown>",
    "collectibles": "<unknown>"
  },
  "reason": "<string>"
}