LeBron will be playing in LA. If he wanted to move, he could have not taken the money and renegotiate the contract or go test the market. The fact that he took he money shows he wants the money more than an extra ring.

Lakers could try to trade him, but no sane team is going to take a $52.6M 1 year contract with a 40 year old guy that could announce his retirement any moment. Think of the amount of assets the team needs to give up in order to take this 1 year contract. Also, LeBron has a no trade clause, which means he also gets to dictate which players the destination team he wants remaining for him to play with. I think a trade like that would be just too difficult to conduct.

LeBron will play out his contract, and maybe he will sign a short term deal with the Cavs as a free agent so he can retire as a Cav. The salary that got freed from his departure will be used to build an awesome team around Luka, with whom Luka will finally win his first championship and bring yet another chip to the Lakers.