I have both fitted from factory and they are very different...
What you are looking to install Is "blind spot assist" or "side assist"
Lane departure warning or "lane assist " is as IT said...
Although there are two variants of the latter. . "Active lane assist " ( actively steers the car hands free to keep you in the lane )
And normal "lane assist " that vibrates the steering wheel when you start to stray over the lines... "essentially simulates the rumble strips found on motorways.