Heavy rain immediately before or during landing can result in hydroplaning just like on the road for a car. Gusting wind from the side can push the plane. Asymmetrical reverse thrust can cause a veered path. Asymmetrical braking will pull the plane to one side. The rudder becomes not effective for controlling landing path below a certain speed. Nose wheel steering and / or asymmetric thrust are used below that speed.
Any of the above or a combination can cause loss of control on a wet runway