LocalScript in StarterCharacterScript is not working?

local plr = game.Players.LocalPlayer
local Char = plr.Character or plr.CharacterAdded:Wait()
local humanoid = Char:WaitForChild("Humanoid")

local UserInputService = game:GetService("UserInputService")
 
UserInputService.InputBegan:Connect(function(input)
    local keyPressed = input.KeyCode
        if keyPressed == Enum.KeyCode.LeftShift then -- put key in parenthesis
                Char.Humanoid.WalkSpeed = 32
        end
end)
 
UserInputService.InputEnded:Connect(function(input)
    local keyReleased = input.KeyCode
        if keyReleased == Enum.KeyCode.LeftShift then -- put key in parenthesis
                Char.Humanoid.WalkSpeed = 16
        end
end)

Why is this not working?