C# Linq Solution

public static List<int> matchingStrings(List<string> stringList, List<string> queries)
{
    List<int> results = new List<int>();

    foreach(string query in queries)
    {
        results.Add(
            stringList.Contains(query) ? stringList.Count(x => x == query) : 0
        );
    }

    return results;
}