Hi! First of all, I would like to say some things that I really like about this drawing! Their poses are very cute and affectionate, and the female lion's low head makes her appear very ill/weak. The mane of the male looks very majestic, making him appear as a high king. Overall, I think you have given these lions personalities by their expression and pose <:3
Anyways, Most of the things I find you could improve on this drawing is your technique. The male lion's mane appears all too perfect, as if someone had given him a thorough comb, and it seems too shiny, as if he has been washing his mane with conditioner. I suggest you perhaps adding a few duller colors to it to lessen the shine, and instead of draw perfectly smooth lines, try to wiggle them a bit to show coarse or disheveled fur. Because it looks so uniformed and perfect, his mane appears a bit 'unnatural'.
Another thing is is the fur direction of his mane. There is a particular clump of hair that overlaps his ear (the one above his ear, to the left). It appears weirdly placed. It looks like it is drooping a bit diagonally, while all the other clumps droop vertically.
The second thing is the female lioness's head. She looks a bit like a wolf because of her eyes, the long fur surrounding her cheeks and her mouth. Her eyes seems a bit too narrow to be a lion's. I think big cats' eyes are very large compared to wolves and their corners are much rounder. For example this lioness's eyes [link] appears much more round and larger than this wolf's eye [link] but the lioness's in your picture resembles more of a wolf. Perhaps you could make the pupil more circular and larger.
Another thing is the fluffiness around her face. Lions, unlike tigers, don't tend to have a lot of long fur around their face [link] [link] the place that has a bit longer fur is mostly underneath their neck or behind their chin and cheeks [link]
and lastly, I think the her snout looks less of a lion because her under lip is mostly hidden. I like one of the lion's most distinctive traits of their large under jaw and the big, fluffy chin. I think when you hid that, she looks a bit less like a lion (to me) of course, this is just my opinion and I'm not too sure about the mouth, so the judgement and decision is all yours ^u^
Ah, I think that's all I hope I didn't sound too bossy/mean XD but really, I do appreciate artists who want critiques because it shows they've worked very hard as an artist. I try my best to help This is a very splendid picture, and I hope you complete it soon so I can see it!