First, the question is biaised : if you consider there was a turning point in the war, this means that one side could have won until the turning point and, after the turning point, the other side took advantage and finaly won.
So if you say there was a turning point it means that Axis could have won the war...maybe, maybe not
I also think that every important event is partly a consequence of events before, so you can not really make one single event standing out.
Anyway, Pearl Harbor is not a turning point, it’s just US entrance in the war. I strongly believe that US would eventualy have entered the war, even without Japanese agression and the following German declaration of war against US.
From this point, war was eventualy to be won by allies because US had the A-bomb.
In the long term, Japan didn’t stood a chance against US.
About Europe, the Eastern Front is the only one that matters. (North Africa was a small scale thing, I guess more soldiers have fought around either Moscow, St Petersburg/Leningrad or Stalingrad than in whole North Africa !)
D-DAY was of a great importance (although you can’t compare with Barbarossa for example),it made the war in Europe end way faster and relieved Soviet forces (and spare the western European countries to fall into Stalin’s hands but that’s another story). But D-DAY was possible only because England managed to win the Battle of Britain (could they have lost this one anyway ?) BoB was Germany’s first important defeat, and a big spank on myth like LW unvulnerability!
On the Eastern front I won’t put Stalingrad in the first place. From a morale and symbolic point of view – which is important – Stalingrad stands out, but I think german lost when they started to loose time at Smolensk and Kiev and were unable to launch attack against Moscow before it was too late.
After Stalingrad, germans were still able to kick soviets in many occasions (failure of operation Mars), but after Kursk (mid-1943) they never gained initiative and Soviets were always on offensive.
So I would say Kursk is the turning point of WWII in Europe, even if as I said above, you can’t speak of a single turining point if any.