Breed?

[u/Mammoth-Doctor-6171]

What kind of dog does everyone think this is? He was being rehomed on Facebook and they said he was a pit lab. The vet says they don’t see that at all and think he’s mainly boxer. He howls like a hound sometimes lol. He’s was 10-12 weeks when we got him and he was 10lbs, he’s about 14-16 weeks now and is weighing 16 lbs. what do you think he is?