Somehow, during transfer of virus from bats to pangolins and then humans, it gained the ability to use its spikes to bind to angiotensin-converting enzyme 2 (ACE2). The virus uses this receptor to enter into the cells, where it can reproduce.
Angiotensin is a hormone that is able to cause vasoconstriction and elevate blood pressure.
The ACE2 receptors are found in lungs, heart, and the gasterointestinale system. The virus is able to enter the cells in these systems and cause cell death.