Usage patterns
〈場所〉に新入りが入るa newcomer joins a place/group
A new employee joined this company again.
新入りを歓迎するto welcome a newcomer
The whole team welcomed the new member.
新入りをいじめるto bully a newcomer
The senior members were bullying the new guy.
新入り扱いするto treat someone as a newcomer
Even though I've been here three years, I'm still treated like a newbie.