3D Model of the robot with rigging and animationThe animation of the robot was made using a Rig.

The *.c4d file includes (an HDR map) and redshift materials which are without any textured or map so you can use it easily.The *.obj and *.fbx have the only model.If you need a model with materials, and HDR, you need to download *.C4DIf you need only the model then you can download *.obj or *.fbx.You need to use Redshift for rendering

HDRI mapHDRI map is free and is downloaded from this website Polyhaven and has CCO License.Polyhaven - you can visit this website and choose another HDRI if you want.You can use it how you want.
The only thing you can't do is claim to be the original author or re-license them.