In the Star Wars universe, we see humans from various real-life ethnic groups playing human characters, but it is not clear whether these characters are intended to be ethnically distinct in universe. For example, Lando is portrayed by an African-American actor, but it is unclear whether or not he belongs to an in-universe ethnic group consisting of people who have stereotypical African-American traits, mannerisms, traditions, or linguistics, or whether his appearance is no more significant than being genetically bald or having Morton's Toe in our universe (e.g. there is no ethnic group in our world with which all bald people align themselves and partake of its culture).
Do humans in the Star Wars universe divide themselves into specific ethnic groups with shared genetics, histories, and/or traditions, or are planet of citizenship, occupation, gender, and faction the only real differentating factors among humans in the Galaxy?
To be clear, we do see that humans on various planets do favor different kinds of clothing and architectural patterns, but it is not clear if those are simply local or civic traditions or whether, for example, distant descendants of human settlers from Naboo on Tattooine would still be expected to retain Naboo traditions, dress like stereotypical Nabooans, speak Galactic Basic with a Naboo accent, self-identify as Nabooan, and/or be seen by those not descended from Naboo settlers as ethnically distinct.