Salut/Hello!
I'm going to assume you meant "All lives matter".
Answer:
"All lives matter" is a slogan that replaces "Black lives matter." Instead of referring just to black people it refers to all the people not depending on their race, nationality, gender, etc.
Reason:
It's trying to point out that black people are sadly killed at double the rate of other races in America.
I hope it'll be useful! :]