void MyMethod(Delegate d){};
 void MyMethod(Expression exp){};
 void MyMethod(object obj){};

MyMethod((int a) => a)

"Cannot convert lambda expression to type 'object' because it is not a delegate type"

void MyMethod(Func<int, int> d){};

void MyMethod(Func<int, int> objFunc)

void MyMethod(Action<int> func) { }

void MyMethod(Action<int> lambdaHereLol)
{
    lambdaHereLol(2);
}

var hurrDurr = 5;
MyMethod(x => Console.Write(x * hurrDurr));

MyMethod((Delegate)(Func<int, int>)((int a) => a));

void MyMethod(Delegate d);