What is a kv_pair?

I am currently trying to work on a function to get the mode of a set of integers, using a hash map. I was given the following to start with:

int GetMode(const vector<int>& input) {
    // assumes the range is [0-10]
    unordered_map<int, int> counts;
    for (int value : input) {
        ++counts[value];
    }
    for (auto kv_pair : counts) {
        // find the max
    }
}

My only question is, what is auto kv_pair? I have never seen this code, so I am not sure what the for loop condition is really looking at to finish this out. Can anyone help out?