As a scientist, I can assure you that there is no conspiracy around not curing cancer. Researchers have been and are working very hard to cure the many different forms of cancer. Treatment is much improved as well. However, polls show that 50% of the public believe in medical conspiracies, so you are not alone. A recent poll also found that 80% of the public want food containing DNA to be labelled. Science education in the USA is dismal.
"In the United States, the overall cancer death rate has declined since the early 1990s. The most recent SEER Cancer Statistics Review, released in April 2018, shows that cancer death rates decreased by:
1.8% per year among men from 2006 to 2015
1.4% per year among women from 2006 to 2015
1.4% per year among children ages 0–19 from 2011 to 2015"
https://www.cancer.gov/about-cancer/understanding/statistics
