I assume that the marked move is the best starting point for Black in the left.
The obvious meets with , after which there is miai to live
If white just push in, I don't see any tricks, which is not to say that there aren't any
It seems a and b are the strongest responses.
After 5 it must be a ko. 2 at 4 is similar.
I think this is the best b can get in this corner.
W must answer 1 with 2, then if W crawls with a and b, B makes an eye with c and d