A sequel to A Plague Tale: Requiem hasn't been officially announced at the time of writing, but work on the series seems to be ongoing at developer Asobo Studio, with open job listings now live for the developer's internal 'Plague Team'.
Basically, the French studio is currently split up as it works on multiple projects, with Microsoft Flight Simulator being the other major franchise in development over there. There are lots of positions ready to be filled for work on Microsoft Flight Sim as the 2024 edition nears release, but there are also four roles available for the A Plague Tale team.