lookVector cannot be assigned to?

lookVector cannot be assigned to

game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 0
player = game.Players.LocalPlayer
hum = player.Character
hum.Humanoid.JumpPower = 0
if hum.Torso ~= nil then
function onKeyPress(inputObject, gameProcessedEvent)
    game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 0
player = game.Players.LocalPlayer
hum = player.Character
hum.Humanoid.JumpPower = 0
    if inputObject.KeyCode == Enum.KeyCode.W then
        hum.Torso.CFrame.lookVector = Vector3.new(-0, -0, -1)
        hum.Torso.CFrame = hum.Torso.CFrame + Vector3.new(0,0,-5)
    elseif inputObject.KeyCode == Enum.KeyCode.S then
        hum.Torso.CFrame = hum.Torso.CFrame + Vector3.new(0,0,5)
    elseif inputObject.KeyCode == Enum.KeyCode.A then
        hum.Torso.CFrame = hum.Torso.CFrame + Vector3.new(-5,0,0)
    elseif inputObject.KeyCode == Enum.KeyCode.D then
        hum.Torso.CFrame.lookVector = Vector3.new()
        hum.Torso.CFrame = hum.Torso.CFrame + Vector3.new(5,0,0)
        end
    end
end

game:GetService("UserInputService").InputBegan:connect(onKeyPress)

i have this grid script that move the player in a grid of 5 studs. i want it to change the lookvector too, but apparantly,

lookVector cannot be assigned to

i get the above error whenever i run this, how do i get it to work right?