when the issue of bitcoins ceases, new coins simply stop creating, that's all. Miners will receive a percentage of transactions. This will not affect the operation of the network.
Another question is what will happen to the exchange rate. On the one hand, an increase in demand with limited supply should lead to an increase in the value of this currency in the medium term. On the other hand, the actions of the Chinese government are playing against bitcoin, and now few will really undertake to predict the course even in the near future.