When does it come?
As soon as Netflix buys the rights.
Unfortunately, this will not be possible for the time being.
Why?
Because Rick and morty is not a Netflix original, that means they have to buy the episodes to be able to broadcast them.
They did it in the first 3 seasons
May not be worth it anymore because no one is watching or they are not interested enough to buy it
OK
You are on the wrong streaming service for Rick and Morty. Until (at least) mid-June the rights for the first 5 episodes of season 4 are still with Sky.