Hey hello! Thanks for the question!

Actually Wholesale Banking is a relative concept to Retail Banking, which the former refers to banking services serving and targeting larger organizations eg larger corporate clients, institutional customers etc. It is a broader concept than Corporate Banking / Commercial Banking and the latter 2 are the sub-sets of Wholesale Banking.

Talking about skillsets, actually it makes no difference from what you can tell from the professionals working in CMB, depending on which roles and departments they are working for. If you are talking about transiting from local banks to HSBC, it mostly relates more about your performance, your customer segments you are serving, and actually may also somewhat relates back a bit to your academic performance / background / languages as well. I wish the link below can give you some more insights:

https://www.investopedia.com/terms/w/wholesalebanking.asp