As we posted below 2 months ago, this has now been confirmed
Thanks to LM for the heads up.
In an appearance on NBC Sports Chicago's Football Night in Chicago, actor and comedian Dan Soder, who plays Mafee, told Mike Berman, "Season seven, the final season of 'Billions,' on its way."
Then, he briefly paused.
"You know... am I not supposed to say that? I don't know if I'm supposed to say that. I think so. It's fine," he said.
"It doesn't matter. You just said it," Berman said in response.
"It's the final season," Soder replied.
Then, he briefly paused.
"You know... am I not supposed to say that? I don't know if I'm supposed to say that. I think so. It's fine," he said.
"It doesn't matter. You just said it," Berman said in response.
"It's the final season," Soder replied.
Source: