When does Slow Horses return?

Slow Horses is a British spy thriller television series based on the Slough House series of novels by Mick Herron. It follows an MI5 unit where disgraced or failed agents are consigned under supervision of Jackson Lamb. The series premiered on Apple TV+ on 1 April 2022 to highly positive reviews.
Slough House is an administrative purgatory for MI5 service rejects who have bungled their job but have not been sacked. Those consigned there are known as "slow horses" - a pun on "Slough House" They are expected to endure dull, paper-pushing tasks, along with occasional mental abuse from their miserable boss, Jackson Lamb.