This year saw new influxes of Central Americans and Cubans on the southern border, Syrian refugees rejected by the leaders of more than 30 states and the president's executive action on immigration mired in legal challenges.
Next year, those stories are expected to play out amid a presidential campaign in which immigration is already a key issue. A look at what's ahead in 2016:
Cuban migrants: Will their special status change?
It's known among Cuban Americans as "the Cuban exception." Under the Cuban Adjustment Act of 1966, Cubans who make it to U.S. soil are entitled to special legal status not afforded other immigrants.
But after the U.S. and Cuba announced last December the beginning of a process to normalize relations, some federal lawmakers have questioned whether such protection is still warranted.
Could it end?
That's still unclear. What's certain is that Cubans are afraid they could lose special status, and are fleeing the island. Cuban migration to U.S. ports of entry in the fiscal year that ended in September was up 78%, to 43,159, compared with 24,278 last fiscal year, according to U.S. Customs and Border Protection.
Their fears may be justified, but they probably will not lose special status soon. Secretary of State John F. Kerry said in the summer that he had no intention of changing the policy, and officials recently reiterated that stance.
The special status granted Cubans may become an issue on the presidential campaign trail, though: Republican Sens. Marco Rubio of Florida and Ted Cruz of Texas, who both have Cuban roots, have been asked to address the issue. Cruz has defended the law. Rubio has said it should be amended to prevent migrants from abusing it.
Syrian refugees: Will states win the right to reject them?
After the Nov. 13 terrorist attack in Paris, in which one of the attackers had a Syrian passport and was believed to have possibly fled the country with refugees, governors in Indiana, Texas and more than two dozen other states vowed to prevent Syrian refugees from resettling there.
Federal officials insisted refugees face extensive screening before they arrive in the U.S. and that states do not have the right to bar individuals based on their nationality.
Some Syrian families already en route to Indiana were resettled elsewhere. The American Civil Liberties Union of Indiana sued the governor on behalf of the resettlement agency involved. The lawsuit is pending.
In Texas, several Syrian refugee families settled in Dallas and Houston. Texas officials sued the federal agencies and resettlement group involved and sought a court order blocking further Syrian resettlement.
A Dallas federal judge rejected the state's request for a restraining order barring new arrivals, but the case is pending.
Executive action on immigration: Will the Supreme Court take the case?
Two executive action programs created by
The programs were designed to allow children brought to the country illegally by their parents, or parents of U.S. citizens or residents, to stay in the United States and work legally.
Texas sued to block the programs, joined by a coalition of 25 states, arguing that they create an undue burden on states, such as the cost of issuing immigrants driver's licenses.
A federal appeals court panel in New Orleans ruled in favor of the states, and federal officials appealed to the Supreme Court, hoping the justices would take the case in time for it to be decided and the programs implemented while Obama is still in office.
Texas attorneys asked for a 30-day extension until Jan. 20 to respond to the federal government's appeal, citing a heavy workload. Instead, the court set a Dec. 29 deadline for those briefs, expediting the process enough to allow for a hearing in January and, if the court takes the case, a decision by summer.
Central American families: Will we see another crisis on the border like last year?
The numbers of migrant families and children crossing are already up, and February will be a crucial month. That's when seasonal immigration traditionally picks up along the southern border.
Fall is supposed to be the slow season, but instead there has been a tremendous uptick in unaccompanied children and families caught trying to cross: more than 10,500 children and more than 12,500 family units in October and November, more than twice the number at the same time last year.
Overall, illegal immigration is down compared with recent years, but violence and deteriorating economies are driving this exodus. Most of the children and families are from Central America — Guatemala, Honduras and El Salvador — although some are also coming from Mexico.
Pope on the border: Will it be safe?
Pope Francis is scheduled to stop in the border city of Ciudad Juarez on Feb. 17 as the culmination of his weeklong visit to Mexico.
Juarez, a city of 1.4 million across from El Paso, Texas, was once known as the "murder capital of the world," plagued by drug cartel and gang violence. But officials say the city has become safer in recent years, although many on the U.S. side are still afraid to cross the bridge linking the two cities.
In a region that is 80% Catholic, enormous crowds are expected to assemble for the event on both sides of the border. El Paso Bishop Mark Seitz said he plans to cross to greet the pope at the Juarez airport and to accompany him during a Mass at the Juarez fairgrounds at day's end.
There, he said, the pope wants to approach the nearby border fence — probably in the popemobile — to greet those assembled on the U.S. side and pray for immigrants who have died trying to cross.