Colloquial contraction of 'kiteiru' (来ている): to have come; to be present/arrived (informal).
待合室に友達がもう来てるよ。
Your friend is already here in the waiting room.
荷物、朝一で来てるはずだ。
The package should have arrived first thing this morning.
もう来てるって電話があったから、準備して出よう。
I got a call saying they're already here, so let's get ready and go out.
(Slang) To be popular or fashionable; something that is currently trendy.
あのバンド、最近すごく来てるよね。
That band is really popular lately, isn't it?
このデザインは今来てるから、店でもよく売れている。
This design is trendy right now, so it's selling well in stores.
若者の間であの言い回しが来てるらしい。
That expression seems to be trending among young people.
(Slang) To be angry or worked up (as in 'to have blown one's top').
彼、さっきのことで来てるから近づかない方がいいよ。
He's angry about what happened earlier, so it's better not to get close.
上司が来てるときは、冷静に対応した方がいい。
When your boss is angry, it's better to respond calmly.