に似てきた

have come to resemble

→ に
phrase Rare #36,824
have come to resemble Used when someone or something has gradually started to look or act like someone else. It combines に似る (resemble) with てくる (come to).
JA: 最近、妹が母に似てきたね。
EN: Lately, my little sister has started to resemble our mother.

だんだんちゃんに似てきた

You're starting to look more and more like Kei-chan.

— 天気の子 (2019)

二人とも大人になって父さんに似てきた

You both have grown up and started to look like Dad.

— グッバイ、レーニン! (2003)

だんだんママに似てきたわね

You're gradually starting to look more and more like your mother.

— 箪笥<たんす> (2003)