What happened to the camera that took the footage of Neil Armstrong's first step on the moon?

Apparently, it's still there! On the Moon, in the Sea of Tranquility, that is.

The camera was stored in part of the lunar landing module that remained behind when Armstrong and Aldrin rejoined Collins in the command module on their return to Earth.

https://airandspace.si.edu/stories/editorial/how-we-saw-armstrongs-first-steps

The reason why the camera remained on the moon was weight.

The camera was a modified Hasselblad 500 EL Medium Format film camera. Due to weight restrictions, the camera carried to the moon was much lighter than the original version. Engineers removed the viewfinder, auxiliary shutter, mirror mechanism and the vinyl coverings in order to save fuel. NASA was so conscious about weight and nervous about running out of fuel during the return flight to the Earth, they decided to leave the camera behind. Armstrong removed the film and discarded the camera on the lunar surface where it remains until today. By the way: The moon rocks Armstrong and Aldin carried to Earth were way heavier than the small camera.