suffix
-ian; -ite; person from ...
Suffix attached to country, region, or place names to indicate nationality, origin, or affiliation. Very productive.
彼はイタリア人です。
He is an Italian.
東京人は歩くのが速いと言われる。
Tokyoites are said to walk fast.
suffix
Suffix indicating a person's profession, role, or expertise, often attached to a field or activity noun. Common in compounds like 芸能人, 文化人, 社会人.
彼女は有名な芸能人だ。
She is a famous entertainer.
社会人になると自由な時間が減る。
When you become a working adult, your free time decreases.
suffix
Used in compound words to mean a person or people of a certain type. Not freely productive; appears in established compounds like 現代人, 外国人, 一般人.
現代人はスマートフォンなしでは生きられない。
Modern people cannot live without smartphones.
外国人観光客が増えている。
Foreign tourists are increasing.
員 is a suffix for members of a group or staff (e.g., 会社員, 店員). 人 is more general and does not imply membership.
From the noun 人 (ひと, person), used as a suffix with the on'yomi reading じん. The suffix usage is well-established and productive for nationality and certain role terms.