When I learned about WWII, figure stood at ~40 million, roughly 20 million in Asia and 20 in Europe (most dead being from China and the Soviet Union).

Estimating these things can be tricky. The perpetrators aren't keeping exact records of how many they kill. In places like China, which was racked by war before the Japanese invasion, the government might not be aware of the exact number of people living in a certain area before it was destroyed by the enemy.

It's also a matter of defining what counts as killed due to a war. Sometimes historians look at "excess deaths" during a period as causalities of war and sometimes they look at a drop average life expectancy as a measure. WWII devastated the economy of the Soviet Union, so maybe it is fair to measure people who died earlier due to not getting health care because of this as casualties of war.