`process.nextTick` and `setImmediate` are both functions that allow certain operations to be executed asynchronously in Node. However, the timing of when these operations are executed can be different depending on which function you use:
1. `process.nextTick` : This schedule a callback function to be invoked on the next iteration of the Node.js event loop. After the current operation completes, whatever callbacks are scheduled with nextTick will be called before the event loop continues.
1. `setImmediate` : This schedules a callback function to be invoked on the next cycle of the event loop. This means it will always execute after any I/O events or timers (like setTimeout and setInterval) in the current cycle of the event loop.
So the key difference is really in when the callback function is invoked. With `process.nextTick`, it will be invoked at the end of the current operation, before any other I/O events or timers fire. With `setImmediate`, it will be invoked after all other I/O events and timers have had a chance to run.
Put simply, `process.nextTick` will run before `setImmediate` and after synchronous operations.
