He worked with Trump. AMLO's a socialist. He worked with Trump because Trump was actually trying to solve the cartel problem, and he was making progress. This let AMLO take steps to 1) increase his own power, 2) promise security to the Mexican people, and 3) he had promises of economic growth from Trump which would have materialized out of the stability.

Of course, as soon as the socialists here stole the election, installed the Biden regime, and turned the CBP into the last leg of the cartels' smuggling operations, the cartels have been running wild. They've got a completely out of control situation. Cartels are flush with cash and rampaging through Mexico. So AMLO's reverting to his socialist roots and embracing the "reconquista" colonization strategy of just moving his surplus population into the US and eventually setting the stage to claim it all for Mexico.