Warning: Each child in a list should have a unique “key” prop. with input – react

i have this:

{array.map((item) => (
                <>
                    <input
                        key={item.id}
                        type="checkbox"
                    />
                    <h3>{item.value}</h3>
                </>
            ))}

and in the website i see the warning: “Warning: Each child in a list should have a unique “key” prop.” but i put the “key” attribute.
does anyone know why?