There are ongoing discussions on the implementation of the next round of new gTLDs (aka "Subsequent Procedures Policy Development Process" in ICANNese). The recommendations of that Policy Development Process are now before the ICANN Board for approval/rejection. Assuming all goes "well", it's likely going to be a few more years before applications for new gTLDs can be submitted. See
https://gnso.icann.org/en/group-activities/active/new-gtld-s... for more info.