The main purpose of this legislation is to improve access to colorectal cancer screening for Medicare beneficiaries by removing the coinsurance requirement for certain tests. This means that individuals covered by Medicare will no longer have to pay a portion of the costs for these screenings, making it easier for them to get tested and potentially catch cancer early. The key provisions of the legislation focus on amending the Social Security Act to eliminate the coinsurance requirement for specific colorectal cancer screening tests.