You're a permanent resident. As the name implies, you're supposed to be able to stay in the United States for the rest of your life.
That's often true. However, it is possible to have the status revoked, and so it's critical to know how this works. Below are four reasons it could happen.
For rather serious crimes, the government will often consider deportation. If you are deported, your status and your green card will be lost. Minor crimes, like a traffic violation, won't lead to deportation.
Perhaps you got your green card because you married someone who was already a citizen of the United States. If it turns out that the marriage is fraudulent and that you only did it to become a permanent resident, you could lose your status.
Other types of immigration fraud
For example, maybe you lied when you filled out the application, or you at least left information out. If you intentionally did anything fraudulent to be granted your status, if it comes to light, you could lose it.
This is when you leave the United States and stay away for too long. You're said to have abandoned your status. You do have an obligation to maintain residency. Often, traveling overseas for at least 180 days per year is enough.
Your legal options
If you're in danger of losing your status, it's very important that you know all of your legal rights. For instance, maybe you have to travel overseas for more than 180 days. There are specific travel documents that will allow it and help you keep your status, but you have to get that paperwork in place in advance.
Source: American Imigration Center, "Can my U.S. Green Card be Revoked?," accessed Nov. 24, 2017