The Careers, who are the tributes from Districts 1 and 2, are known for their strength, skills, and ruthlessness. They are trained from a young age to be deadly fighters, and they usually dominate the Games.
District 4, known for its fishing industry, provides the Careers with valuable resources, such as fishing nets and hooks, which they can use to hunt and trap other tributes. In exchange, the Careers offer protection and support to the District 4 tributes.
This alliance is highlighted in *The Hunger Games* book and movie, where the Careers are shown actively recruiting the District 4 tribute, Marvel, into their group.
It's important to note that while this alliance is beneficial for both sides, it doesn't necessarily guarantee survival for the District 4 tributes.