The Canon EOS-1D X Mark II is Canon’s top dog, the Canon DSLR for professionals. Period.
Announced three years ago, the EOS-1D X Mark II isn’t yet ripe for replacement. Most high end Canon DSLRs have a longer lifecycle. However, it seems Canon is already actively working on the EOS-1D X Mark III.
The announcement of the EOS-1D X Mark III might come at the end of 2019 or the beginning of 2020. It’s still a long time to go.
Rumor has it that Canon might release the EOS-1D X Mark III ahead of the Olympic Summer Games in Tokyo, Japan, which start July 2020. No specifications leaked so far, besides that the EOS-1D X Mark III will be more of an evolutionary than revolutionary update.
There have been rumors suggesting Canon might ditch the EOS-1D X line in favour of a mirrorless offering. This is unreal for the time being. It will take years before the folks shooting at events like the Olympics will switch from their trusted workhorses to a new technology.