Here are some examples of present perfect tense of the verb "to be"
I have been sick since yesterday. ( I got sick yesterday and I am still sick)
He has been late every day this week. ( He was late on Monday, Tuesday, and Wednesday. Today is Thursday, and he was late today, too.)
You have always been my best friend. (You were my best friend in the past, and you are my best friend now.)
This is different. It is the present perfect progressive tense of the verb "live".
They have been living next to us for three years. (They moved to the house next to us 3 years ago. They are living there now.)