float steer = CrossPlatformInputManagerGetAxisSteerW;

This line of code is used to get the value of the "SteerW" axis input from the user. The value of the input is stored in the variable "steer" as a float data type. This input can be used to control the steering of a vehicle or any other object in a game. The "CrossPlatformInputManager" is a Unity API that allows for cross-platform input management, meaning it can handle input from different types of controllers (keyboard, mouse, joystick, etc.).