This means it's essentially the same vehicle as the regular Escalade but with a significantly longer wheelbase. This extra length translates to substantially more passenger and cargo space in the third row and behind it. Everything else – the engine options, luxury features, technology, and general design – is largely the same as the standard Escalade, just stretched out.
In short: Think of it as a Cadillac Escalade, but bigger and with more room for passengers and luggage.