Background image not appearing in motion tracking render I have another project that is exactly like this one but that one works, even though they have the exact same compositing setup. Any reason why this one doesn't show the background?

Blend file: https://drive.google.com/file/d/1Zsjwe7C50eo_h7rROzzBAzxy1M5y_gZI/view?usp=sharing
You need a layer with Alpha information if you use alpha over.
As you can see in the preview in the node editor your background is  gray instead of transparent.
To fix this just go to the properties window -&gt; Render -&gt; Film and tick transparent.