The last time we saw John Oliver on “Last Week Tonight,” the weekly comedy series he hosts for HBO, he was blowing up a giant 2016 sign in a soccer stadium, bidding farewell to a year that seemed unmatchable in its capacity for tumult and forehead-pounding news events. Then 2017 came along.

As Mr. Oliver prepares for the fourth-season premiere of “Last Week Tonight” on Sunday, he returns to an arena where President Trump, the bête noire of the late-night shows, has been in charge of the country for nearly a month. During that time, the Trump administration has already made the picture more complicated for many issues that Mr. Oliver has addressed in his long-form segments, like net neutrality, voter fraud, torture and nuclear weapons.

Now, who wants to hear some jokes?

In an interview on Monday at HBO’s New York offices, Mr. Oliver, 39, said that despite some clear challenges to his way of looking at the world, he did not believe his past work had been in vain. “I’m not a complete nihilist,” he said with a laugh. “I haven’t quite got to the point where I’m going, ‘What’s the point in anything? Burn it down.’”

Though he was mum on the subject of Sunday’s episode, Mr. Oliver said “Last Week Tonight” would continue to resist the impulse to go “all Trump, all the time,” and instead try to focus on subjects not addressed by his late-night peers. “It’s a lot of people feeding on the same carcass,” he said. “We try to pick a different carcass because of how many different beaks have already gotten to it.”