Normally they both share certain similarities but I'd mention one. They both have to do with trading currencies. Forex trading deals on trading one fiat currency for another hoping that it rises in value, same way crypto trading deals on buying and selling of digital currencies but this time in crypto currencies only which could later be converted to get profit.So one could say that they're similar but different
In many ways than one they are similar. In purpose, strategy like FA and TA, indicators etc they are same but the difference are that the government is involved in forex trading because it is the fiat currency of different countries but cryptocurrency is not regulated and not monitored. The platform for cryptocurrency is usually exchanges and they can manipulate your coins. In terms of forex, they are registered brokers that are known in different countries based on the one you choose mostly they operate with the banks directly as they pay your profit direct to your bank account but cryptocurrency, you have to receive your profit in cryptocurrency.