Uncharted 4 like movement and climbing

Hello does anyone here know how Naughty dog made the movement in Uncharted 4 so smooth? if you look at the movement in the game it looks really smooth. If you run forward and then back or left and right it has some really cool movements in the middle that makes it look so smooth and amazing same with the climbing. Does anyone know how they made it look so realistic or smooth. The default running animation in UE4 looks kinda “basic” and there is no change in movement when you move side to side or forward to 180. Uncharted 4 also has a very realistic start to the run. Does anyone know how they made it so good? i’m a noob at this and i thought it was just animation to this animation and so on but it seems so much more complicated than that.