old haunts; former home; old nest
Refers to a place one used to frequent or live in, often with nostalgic or figurative overtones. Can be used for a former workplace, team, or group.
彼は久しぶりに古巣のチームに戻った。
He returned to his old team after a long time.
He returned to his old team after ten years.
引退した選手が古巣の球場を訪れた。
The retired player visited his old home stadium.
She decided to leave the company she had worked at for years.
The player ended up facing his former team.
古巣 is a casual, figurative term for one's former home or old stomping ground, while 生家 formally denotes the family house itself.
Compound of 古 (old) and 巣 (nest), literally 'old nest'. The figurative extension to familiar places or groups is natural from the nest metaphor.