Here is a sample to find if there are match elements in another list
List<int> nums1 = new List<int> { 2, 4, 6, 8, 10 };
List<int> nums2 = new List<int> { 1, 3, 6, 9, 12};
if (nums1.Any(x => nums2.Any(y => y == x)))
{
Console.WriteLine("There are equal elements");
}
else
{
Console.WriteLine("No Match Found!");
}