Hunger of Hadar says:
A 20-foot-radius void appears on a point you choose. Its filled with whispers and slurping that can be heard up to 30 feet away. No light can illuminate the area, and creatures fully in it are blinded. The void's area is difficult terrain. Any creature that starts its turn in the area takes 2d6 cold damage. Any creature that ends its turn there must succeed on a Dexterity save or take 2d6 acid damage.
Almost anyone can see in
Hunger of Hadar doesn't prevent people with darkvision from seeing into it. The only thing that stops people outside from seeing in is that the area is unlit. Devil's Sight thusly confers no advantage in this situation, beyond the additional range with the darkvision as compared to most races. The only people who can't see in, then, are those who few weirdos who lack darkvision (i.e. halflings, humans, and dragonborn without class features to the contrary).
It's important to remember that spells only do what they say they do; while Darkness creates magical darkvision-stopping darkness, it does so because it says it does. Other magically created darkness is just dark.
Almost no one can see out
Hunger of Hadar doesn't stop you from seeing out cause it's dark. Hunger of Hadar stops you from seeing out because it inflicts the 'blinded' condition. That's a much stronger condition that just 'I can't see'; even with blindsight you are still subject to "Attack rolls against the creature have advantage, and the creature’s Attack rolls have disadvantage."
Indeed, rather than mere blindsight or tremorsense, a more powerful ability like immunity to the blinded condition would be needed to render Hunger of Hadar ineffective against a target.
So, Devil's Sight doesn't really matter
Like was said on twitter:
Devil's Sight is meant to pierce the dark created by a spell like darkness, not the void of hunger of Hadar.
That's not because you can't see in with it; that's because you'd be able to see into it anyways. The cool thing Devil's sight lets you do is see through magic darkness you otherwise wouldn't have been able to. The rest of the time it's just fancy darkvision.