split screen with different tracking effects?

Hi, Zina Khebaouet!

There are couple ways to do this. The simplest might be next: 

You could create a two different cameras that render different effects (check out Render Layers guide)

Then create two opacity textures (half white half black, and same but inverted) and set them as a Mask parameter of the Camera component.

As an alternative you can also achieve this combining render targets from both cameras in material editor. 

Project Example

Let me know if you have any further questions!