There's therapeutics for HIV that make symptoms disappear and transmission near 0, there's been huge strides in HIV treatment in the last 30 years. There's even preventative meds for people who are at an increased risk of contracting HIV. And "cancer" is actually a collection of dozens and dozens of illnesses, so it's not just a matter of finding a vaccine or cure for a single thing. Each person's tumor is unique which increases the research needed exponentially. Regardless, there are some vaccine solutions to cancer. HPV can cause cervical and other types of cancer and there's been an HPV vaccine for quite a while. Hepatitis B can cause liver cancer and there's a vaccine for that. There's all sorts of new immunotherapy which can be tailored to the individual to fight their unique cancer. There's a flu vaccine that would be good against all variants that's on the horizon, and would work similar to how the military vaccine for covid that is currently going through human trials by attacking commonalities of all variants. As someone who's chronically ill and has had cancer, there's lots of improvements, early treatments, and things that can improve one's quality of life anymore, and they're always getting better.