I want to point out that 1/3rd of all humans on the planet are infected with TB, but it's dormant in most of these. TB is probably the no. 1 secondary infection killer that strikes when a person's immune system is weakened. It was the no. 1 killer of people with HIV in developing nations prior to antivirals (I don't know the stats now, sorry).

So, a vaccine against TB would save countless lives.

Additionally, because it's sitting in so many people, it's ripe for natural selection. If we don't eliminate this threat, it will come back worse. I believe it was in 2012 that total drug resistant TB evolved - if we don't shore up our healthcare systems, it'll gain a foothold in developed nations shortly.