The social security system refers to a social security system that, under the management of the government, in accordance with certain laws and regulations, through the redistribution of national income, and relying on social security funds, to provide material assistance and services for the protection of people's lives.
 Uncle Li, a retired employee, was diagnosed with lung cancer not long ago. The operation and other treatments cost hundreds of thousands of yuan, and most of the medical expenses are reimbursed by the medical insurance agency is within the scope of the social security system.