Here is another robot kit for Raspberry Pi that lets you build your own robot tank. The XiaoR Geek Raspberry Pi Robot Tank comes with a 720p camera, tank tracks, WiFi adapter, and app control. You can interact with the robot from your iOS/Android/PC.
This robot tank can climb up to 30-degrere slopes. It has a 4 DOF robot arm too. The kit ships with Raspberry Pi 4B, chassis, power supply, and everything you need to get started.