Lats under tension from full stretch to squeeze.
Keep the elbow angle fixed. Sweep with the lats, don't turn it into a pressdown.
The cable pullover is a pull for your back with the arms taken hostage, elbows locked in a slight bend so your lats alone sweep the bar from an overhead stretch down to your thighs, with your chest assisting through the arc. Because your biceps never get to bend and help, it isolates the lats in a way rows and pulldowns can't. It earns its place when you want to actually feel your lats working, or to add back volume without further taxing your arms and grip.
The pulldown bends your elbows, so your arms share the work. The pullover keeps your arms long with a fixed elbow angle, making your lats move the weight almost alone, less load, far more isolation.
Down the sides of your back, from behind your armpits toward your waist, with some chest involvement as the bar sweeps down. If it's all triceps, your elbows are bending and straightening, lock the angle and lighten the stack.
Both work. The bar keeps your hands fixed and the path consistent, the rope lets your hands finish slightly apart for a touch more freedom at the bottom, pick whichever lets you feel the lats most.
