2015 Jeep Cherokee Tires

I've had these tires on the rear of my Jeep Cherokee for about 40,000 miles. So far the tread wear has held up great, they are probably still at 1/2-3/4 tread remaining, however I noticed the tires becoming louder and louder recently. Took at look at the tires, and it seems that the insides of BOTH rear tires have worn in an extremely strange way. Some tradblocks have worn more than others (like every second one) on the inside two treadblocks of both rear tires. Normally if the alignment or camber would be off, they would wear the inside tread evenly, but this is just strange! I thought the wheel bearings were bad because it creates such a bad noise "whomp whomp whomp" as the wheels turn! Otherwise all the tread has help up great. Really disappointed because now I have to get entirely new tires, even though the tread seems mostly fine.