The cause was pneumonia, a complication of esophageal cancer, said the magazine Vanity Fair, which announced his death.
No, the immediate cause was catching pneumonia in a hospital for the 3rd time and having a too-weakened immune system from the cancer treatment to outlast it. It's not a complication of esophageal cancer; it's a complication of esophageal cancer treatment and badly sterilized hospitals. So many people die from pneumonia they caught in hospitals.
But I didn't expect him to last into this year even. Shows how strong he was, writing up to his last days.