I just want to thank you for reaching out to us in our forums! That is a great question! You can post this particular cable box manufacturer and model number in our remote control requests community. We do have people that are developing our newest remotes from the feedbacks from that community. You can also check out our newest remote additions on What's New part of our support page.
I hope you find this information helpful!
Have a Great Day!
The Sling Moderation Team