The Cleveland Cavaliers can't trade LeBron James without the permission of LeBron James. This isn't some cute way of saying LeBron is actually the general manager of the organization and David Griffin isn't making the decisions. Griffin is definitely sculpting the team like he's done the last couple of years. But LeBron is one of the rare players in the NBA with a no-trade clause -- joining Kevin Garnett, Dirk Nowitzki and Carmelo Anthony as the only players to have this option.
To get a no-trade clause in the NBA, you must have at least eight years of service in the NBA and four years with your current team when you become a free agent and sign the new contract. It can't be given out on contract extensions, which is one of the reasons it's so rare to see it. Players often move around enough now to make them ineligible for such a stipulation. Via The Vertical's Bobby Marks:
On the LBJ contract. James joins Melo, KG and Dirk as players with a no trade clause. 8 seasons and with current team 4 yrs to be eligible.— Bobby Marks (@BobbyMarks42) August 15, 2016
In order for the Cavs to trade LeBron at some point, they'd have to get him to agree to waiving his no-trade clause, much like the Minnesota Timberwolves had to convince Garnett to do when they swapped him for Thaddeus Young as they brought the future Hall of Famer back to his first franchise in the league.
We probably won't see that or anything close to it with LeBron and the Cavs. After bringing them their first title in franchise history, it's safe to say he'll stay with the team as long as he wants and the Cavs will be happy to have him there.