In year 2009, 1.1 million bitcoins are mined which is 5.24% of the 21 million bitcoin that can be mine in the system. Today, 13 years after the first set of mined bitcoin there are already 19.19 million bitcoins in existence or 91.38% of the total bitcoin. Which means that 1.8 million bitcoins (8.57%) are left to be mine, if you are wondering when will all bitcoins be mined, professionals says that it will take another 120 (more or less) years to mine the remaining millions because of bitcoin halving. Bitcoin halving happens about every 4 years, the Bitcoin block reward that usually get by the miners are cut in half.
so, what are your thoughts when all Bitcoins are mined?
Since the block reward is halved every roughly 4 years, in a decade or two we'll already see transaction fees taking over as the main incentive for miners. After that happens, the block reward will start playing a secondary role in mining incentives, and gradually will become irrelevant.
Miners will continue to mine after the last bitcoins are received as incentive because at that time they will be getting mostly paid in transaction fees.
So, basically, everything will continue in a similar way. Tick tock, another block.