A throwaday comment in an interview or a sign that Big Brother could one day return to it's rightful home:
deadline.com
I do think it'll return to C4 one day, but not quite yet - and I think it needs a few more years off screen. C4 have The Circle for now - though still not officially recommissioned rumour is it'll air twice a year for the next couple of years, by which time that franchise may begin to burn out and resurrecting Big Brother could be the obvious next step. And as much as I'd like to see the UK give the BBUSA/Canadian format a try, the most successful new UK reality show of the year was the fairly stripped back Race Around the World, a show that felt like the reality TV of two decades ago. At the moment I think stripping BB right back to basics might be the right option.

Channel 4 Boss Ian Katz On ‘Big Brother’ Revival, ‘The Circle’ Renewal & E4’s Hunt For Tentpole Reality Show
In an exclusive interview with Deadline, Katz said he would not dismiss an approach from Endemol Shine Group over Big Brother.

EXCLUSIVE: Channel 4’s director of programs Ian Katz has said he would consider bringing back Big Brother, and revealed that youth channel E4 is conducting a major hunt for a new reality show.
In an exclusive interview with Deadline, Katz said he would not dismiss out of hand an approach from Endemol Shine Group producer Initial after Viacom’s Channel 5 ditched the longrunning reality show last year.
Asked if he would revisit Big Brother, he said: “I’d keep an open mind about pretty much any format.” Katz later added: “One of the things we’ve learned in the last few years is how effectively almost any historic format can be rebooted in really interesting, creative ways.”
I do think it'll return to C4 one day, but not quite yet - and I think it needs a few more years off screen. C4 have The Circle for now - though still not officially recommissioned rumour is it'll air twice a year for the next couple of years, by which time that franchise may begin to burn out and resurrecting Big Brother could be the obvious next step. And as much as I'd like to see the UK give the BBUSA/Canadian format a try, the most successful new UK reality show of the year was the fairly stripped back Race Around the World, a show that felt like the reality TV of two decades ago. At the moment I think stripping BB right back to basics might be the right option.