When you want to figure out the CMB meaning in text, read the context of the message and the topic that is used. If someone just rang you or is asking for a private chat, it most likely that CMB means "Call Me Back". For example, a message such as, "Need help, CMB ASAP. " is clearly asking for a telephone call. The use of abbreviations on the internet can have many meanings, one way to be sure is by the use of context. Tone of writing, platform, and the way communication is taken place can help understanding of slang words and abbreviations like CMB.
