In addition to the path made by 5G (small cell coverage, massive mimo, mm-waves, etc ), 6G is going to merge other areas such as bio-medical, artificial intelligence, robotics, etc.
What are the key enabling technologies of the 6G networks?
my short list of sources of information about 6G systems includes information on key technologies, research challenges, and visions.
These sources will give you a detailed answer to your question.
Best regards
Anatol Badach
Xiaohu YOU, Cheng-Xiang WANG,et al.: „Towards 6G wireless communication networks: Vision, enabling technologies, and new paradigm shifts“, SCIENCE CHINA Information Sciences, May 2020
Mohammed H. Alsharif, Anabi Hilary Kelechi, Mahmoud A. Albreem, Shehzad Ashraf Chaudhry, M. Sultan Zia, Sunghwan Kim: Sixth Generation (6G) Wireless Networks: Vision, Research Activities, Challenges and Potential Solutions; Symmetry, Apr. 2020; doi:10.3390/sym12040676
https://www.mdpi.com/2073-8994/12/4/676
Yifei Yuan, Yajun Zhao, Baiqing Zong, Sergio Parolari: Potential key technologies for 6G mobile communications; Science China Information Sciences, Vol. 63 , Issue 8, 2020 https://engine.scichina.com/publisher/scp/journal/SCIS/63/8/10.1007/s11432-019-2789-y?slug=fulltext
Bernard Barani: Beyond 5G, a European Perspective; Jan. 2020 https://www.itu.int/en/ITU-T/Workshops-and-Seminars/20200113/Documents/Bernard_Barani.pdf
Mika Ylianttila et al. (Ed.): 6G White Paper: Research Challenges for Trust, Security and Privacy; Apr. 2020 https://arxiv.org/ftp/arxiv/papers/2004/2004.11665.pdf
Marco Chiani, Enrico Paolini, Franco Callegati: Open issues and beyond 5G https://www.5gitaly.eu/2018/wp-content/uploads/2019/01/5G-Italy-White-eBook-Beyond-5G.pdf
Matti Latva-aho, Kari Leppänen (eds.): 6G Research Visions 1: Key Drivers and Research Challenges for 6G Ubiquitous Wireless Intelligence; While Paper; University of Oulu: Oulu, Finland, Sept. 2019 http://jultika.oulu.fi/files/isbn9789526223544.pdf
Petri Ahokangas, Hirley Alves et al.: Key drivers and research challenges for 6G ubiquitous wireless intelligence (white paper); Sep. 2019 https://www.researchgate.net/publication/336000008
I would really recommend you to have a look at my recent paper (6G Wireless Communications Networks: A Comprehensive Survey). Many technologies have been discussed, which I believe will be part of future 6G wireless communications networks.