Anything that changes is an illusion, but the illusions are still real things.
When a trickling of water flows downhill it is called a stream, but what it is exactly? It is not a thing that you can hold since when you bottle up the water it no longer becomes the stream. The stream is a process, a doing, not a thing in the object sense; "streaming" should be a better definition.
It is the same with "living". There is no actual life; only living.
The illusion is that life is a concrete object, and who are we to say other wise: we touch ourselves and are touched by others, hear ourselves and hear others. We have a body and a mind, but what happens at death? The body and mind cease to be and with it, the life.
The life comes and goes, but "living", the process and action of it, never truly dies. The perception of our world by way of our senses is the only true thing there is. We touch, we see, we smell, we hear; and we use these real things to build an artifice that we call "the body" and "the psyche".
The body and psyche are created out of quite literal thin air; the hot breath that left the lungs out of the mouth and vibrated your eardrums to tell you your name, your race, your religion, your relations.
The sound waves that convey meaning through language are filtered through the ears and are met by the mind who files and sorts by importance. The import is attached to the feelings; the stronger the feeling attached to the information, the tighter and more vividly the mind holds on to it.
But where is the mind?
The ancient master Bodhidarma who brought what is now referred to by the Japanese tradition as Zen to China, told a student whose mind was turbulent and troubled to bring his mind out before him in order to pacify it. But when the student looked for his mind to show the teacher, he could not find it.
Bodidharma said "that is your answer".
Are "you" your body or your "mind"? Are you neither of these?
Well, who are you?
What are you?
Can you define yourself?
I am the exact same as you, but still different.
How am I different? I know who I am, you just don't know who you are.