LAS VEGAS, U.S. -- The world's biggest consumer electronics and technology expo officially kicks off Tuesday, with 170,000 attendees expected to converge on Las Vegas for CES 2020.

The annual four-day gathering, formerly known as the Consumer Electronics Show, will feature the latest advances in 5G, blockchain, artificial intelligence and other cutting-edge tech.

What the first major tech event of the new decade won't feature, however, is a strong Chinese presence. With the protracted trade tensions and a technological decoupling between Washington and Beijing, the big Chinese tech companies -- Alibaba Group Holding and Tencent Holdings -- will not exhibit in the show.

Here are five things to watch at CES 2020.

What are the key tech trends at the show?

While the past few years have been about the "internet of things," 2020 is expected to kick off a new decade defined by the intelligence of things: connecting artificial intelligence-enabled devices such as smartphones and TVs to transform living spaces.

"Over the next 10 years, the dynamic of connected intelligence will grow apace with advancing 5G networks and innovative applications of AI," said Steve Koenig, vice president of research at Consumer Technology Association, the organizer of CES.

Another focus of this year's CES will be health and wellness tech, with a 25% increase in exhibitors in the segment. And it is about more than smartwatches and advanced sensors. "We're going far beyond devices to AI-assisted diagnosis, remote robotic surgery and more," said Koenig.

Smart city technology will also have a bigger presence at CES 2020, with exhibitor numbers up about 25% and exhibition floor space up 70%.

Two other trends to note this year include the continuing rise of new transportation technology, largely autonomous driving and flying cars, along with virtual reality and augmented reality. Green technologies are another hot topic, covering everything from sustainable farming and alternative meats -- Impossible Foods is among the attendees -- to energy and the environment.

And as technology becomes ubiquitous, nontraditional tech companies such as Delta Air Lines and DuPont are joining the event.

Is 2020 the beginning of the 5G era?

Industry watchers see 2020 as the year when fifth-generation wireless technology will finally be commercialized at scale. Countries like China and South Korea rolled out 5G networks in 2019, and Samsung Electronics recently said it shipped more than 6.7 million Galaxy 5G smartphones last year.

With more countries and companies expected to follow suit this year, it is little wonder that 5G is one of the biggest buzzwords at CES 2020. At least 17 sessions devoted to the technology are scheduled during the four-day event, with topics ranging from how 5G will change personal lives to its impact on manufacturing, health care, agriculture and other sectors of the economy.

"5G and AI are the real game changers because they will change everything and eventually touch every device in some way," Koenig said, adding that early adopters will focus on the consumer market before expanding into enterprise applications. He added that CES 2020 would showcase some 5G-enabled consumer devices such as smartphones and gateways.

How will U.S.-China tensions impact the show?

The Chinese exhibit space is expected to shrink from last year, according to CTA. The decisions by tech heavyweights, Alibaba and Tencent to stay away come as little surprise, given that Washington blacklisted their compatriot Huawei Technologies and several Chinese AI startups over the past year.

Attendees from all industries will be closely watching whether Washington and Beijing sign a trade deal on Jan. 15, though a year of uncertainty has already sparked a divergence between U.S. and Chinese tech worlds -- a great decoupling that could have profound repercussions for years to come.

Another major factor discouraging Chinese companies from attending involves logistical issues hampering U.S. visa approvals, especially for individuals who work in sensitive fields such as artificial intelligence and semiconductors, Nikkei has learned.

"Our company decided not to attend this year because we knew it would take forever to get our visa, if they don't get rejected after all," said the founder of a Chinese AI chip startup who was identified only as Lu.

What will be the highlights for GAFA?

The four big American digital platforms -- Google, Apple, Facebook and Amazon -- often set the tone for CES events, and their exhibits are always closely watched. Their notable focus this time is on security and privacy.

Amazon, Apple and the Zigbee Alliance announced in December that they will collaborate on a common connectivity standard for smart home products, with an emphasis on security. Zigbee includes Samsung SmartThings and China's Wulian. The collaboration comes amid concerns in the U.S. over privacy and data protection, particularly related to joint efforts between American and Chinese players.

While Apple is not on the exhibitor list, its chief privacy officer will make a rare CES appearance in an official talk session with Facebook's CPO. The tech giants have already come under government scrutiny due to privacy concerns, and the issue is growing more pressing as they attempt to collect even more personal data, such as in the sensitive medical segment.

What do we expect from Asian companies?

While fewer Chinese companies are showcasing this year, some big names are still attending. These include consumer electronics brands Haier and Hisense, electric vehicle startup Byton and drone maker DJI. Huawei is also on the exhibitor list, although it is likely to stay relatively quiet.

South Korea, by contrast, will have a strong presence, with Samsung scheduled to give an official keynote speech. The company's consumer electronics president, Kim Hyun-suk, will speak about "revolutionizing the consumer lifestyle." Hyundai Motor, meanwhile, says it will unveil its first concept "flying car."

About 70 Japanese companies will attend. In addition to regulars such as Toyota Motor, Sony and Panasonic, there will be some first-time exhibitors including Kyocera, NTT and sports brand Asics.