Tutankhamun’s heart was missing when scientists examined his mummy. This is extremely unusual. Usually, when a Pharaoh was mummified, the heart was kept inside the body. For a Pharaoh to be accepted into the afterlife - his heart must be intact.

Why did the embalmers remove his heart?

It could be because he died far away from home and by the time his body was mummified, the heart had decomposed. There is also a suggestion that Tut had sustained an injury to his chest and his heart was too badly damaged to embalm. He was instead given an amuletic scarab in place of his heart - inscribed with a funerary spell so he could walk in the field of reeds.