A newcomer; someone who has just joined a group or organization (a rookie or initiate).
今日から部署に新入りが一人来ました。
A new person joined the department starting today.
サークルの新入りは自己紹介をした。
The club's newcomer introduced themselves.
最初は新入りとして地道に経験を積むべきだ。
At first you should steadily gain experience as a newcomer.