a > b ? (return a) : (return b);

This is a ternary operator statement in JavaScript. It checks if the value of variable 'a' is greater than the value of variable 'b'. If it is true, then it returns the value of 'a', else it returns the value of 'b'.

It can be rewritten using a traditional if-else statement as:

if (a > b) {
return a;
} else {
return b;
}