The half million figure accounts for both combatant and civilian deaths from direct fighting and war violence, however the number could be much higher as the study didn't account for the perhaps far higher number of civilians killed through infrastructure damage, such as hospitals or water supplies becoming inoperable, or other indirect results of the wars.
Tragically, civilians make upover 50% of the roughly 500,000 killed, and the study estimates further that both US-backed foreign forces and opposition militants each sustained over 100,000 deaths.
In terms of American forces, the report finds that over 60,000 US troops were either killed or wounded within the three post 9/11 conflicts. This includes 6,951 US military personnel killed in Afghanistan and Iraq since US invasions of those countries in 2001 and 2003.
Concerning the now seventeen year long "forgotten war" in Afghanistan, the study concluded, according to VOA:
Some estimates in the past compiled by independent watchdog groups and polling organizations have put the death toll in Iraq alone at over one million people.