A casual way to ask someone how they've been recently; equivalent to "How's it going?" or "What's up?"
学生時代の友人に久しぶりに連絡して『最近どう？』と聞いた。
I contacted a friend from school after a long time and asked, 'How have you been lately?'
LINEで『最近どう』と送ったら、すぐに近況の写真が返ってきた。
When I sent 'How's it going?' on LINE, they immediately replied with recent photos.
会ったときに『最近どう』と軽く声をかけるだけでいい。
When you meet, it's fine to just casually say 'How have you been?'