Ref vs Out in C#

using System;

namespace Ref
{
    class Program
    {
        static void Main(string[] args)
        {
            {
                int a = 4;
                int b = 3;
                int result; // unnecessary assigment of a value to result when we use out
                GetSum(a, b, out result);
                Console.WriteLine($"The sum from {a} and {b} is {result}.");
            }
        }

        private static int GetSum(int first, int second, out int result) // first and second are passed by value, but result is by reference
        {
            result = first + second;
            return result;
        }
    }
}