* As an adjective: Generally, "tribal" is not capitalized when used as an adjective describing something related to a tribe, such as "tribal customs" or "tribal art."
* As a noun: If "tribal" refers to a specific tribe or group of tribes, it may be capitalized, especially when it's part of a proper name, such as "the Tribal Council" or "the Navajo Tribal Nation."
It's always best to consider the specific context and the name being used to determine if capitalization is appropriate.