How to check list A contains any value from list B?

Question

List A:

1, 2, 3, 4

List B:

2, 5

How to check if list A contains any value from list B?

e.g. someth

Answer 1

I use this to count:

int cnt = 0;

foreach (var lA in listA)
{
    if (listB.Contains(lA))
    {
        cnt++;
    }
}