What’s the difference between returning a funcition in an if statement and placing the function body in an if statement?

I realized that this code

function(todo) {
  if(!todo) { return }
  // some stuff here
}

and this code

function(todo) {
  if(todo) {
    //some stuff here
  }
}

gets you the same result. When the function is called, if the todo argument is truthy, then the “some stuff” gets executed. Is there any diference between these 2 approaches?