This week saw several high-profile exchanges between officials from the United States and China, beginning with a phone conversation between Presidents Donald Trump and Xi Jinping last Friday (September 19).As we noted in last week’s tracker, the call came after negotiators agreed to a framework for the Chinese-origin app TikTok to continue operating in the US. Trump has batted for the app in recent months, citing the support he received from young voters in the 2024 elections.Then on Sunday, a delegation of US lawmakers from the House of Representatives visited China and met senior officials, including China’s Premier Li Qiang. This was the first such visit since 2019.Amid the H-1B visa-related upheaval in the US, China’s new category of K visas was in the news. Details will be out next week, but we explained how it compares to the existing visa regime and its possible impact.Finally, China made some new climate commitments for 2035 during a special UN climate summit on the sidelines of the annual United Nations General Assembly gathering in New York.Here is a closer look at these developments:1. Trump-Xi call on future meeting, TikTok divestitureTrump described the call as “very productive” on his social website, Truth Social. He said progress was made on issues like trade, China’s role in the smuggling of fentanyl opioids in the US, the “need to bring the War between Russia and Ukraine to an end”, and the TikTok deal.He added that the two leaders will meet at the Asia-Pacific Economic Cooperation (APEC) Summit in South Korea in November, and that he will visit China “in the early part of next year,” with Xi reciprocating soon.Story continues below this adUPSHOT: In an executive order on Thursday, Trump extended TikTok’s deadline to comply with a law for regulating “foreign adversary controlled applications” to December 16.Several important provisions were announced for the app. There will be a divesting of TikTok’s US operations, the app will be majority-owned and controlled by United States persons, and ByteDance Ltd. (the Chinese parent company) and its affiliates will own less than 20 per cent of the entity.Trump’s executive order said, “I have determined that the proposed divestiture would allow the millions of Americans who enjoy TikTok every day to continue using it while also protecting national security.” It added that around 170 million people used the app, which is about half the total US population.That a key sticking point has seen steps towards a resolution is good news for the bilateral ties, as are announcements of future meetings. Issues beyond the scope of the call, such as the US’s complaints about China engaging in unfair trade practices, still loom large, but the two sides have held multiple rounds of talks in recent months to improve cooperation.Story continues below this ad2. US lawmakers visit China, focus on military talksUS Representative Adam Smith, a senior Democrat on the House Armed Services Committee, led the bipartisan delegation’s trip to China. They met senior officials such as Foreign Minister Wang Yi, Chinese Defence Minister Dong Jun and Cai Qi, Secretary of the Secretariat of the Chinese Communist Party.Speaking at a news briefing in Beijing on Tuesday, Smith said the delegation’s goal was to “open up the lines of communication”, adding, “Our relationship is going to be the most consequential relationship in terms of what the world is going to be like for decades to come.” He said that military-to-military communications also needed to be maintained.UPSHOT: US-China military communications were suspended for over a year starting in August 2022. It followed a visit by then-US House Speaker Nancy Pelosi to Taiwan, which China claims as its own territory, forbidding other nations from recognising it diplomatically. Military information also matters in the context of China’s increasing assertions, including in the South China Sea and the Taiwan Strait. Just earlier this month, Beijing hosted a massive military parade which revealed advancements in its capabilities.A meeting between Xi and then US President Joe Biden led to the restoration of communications in August 2023, but their lowered frequency matched the downward trend in the broader ties, too.Story continues below this adAs a report in The Diplomat noted recently, “[US] Government-sponsored exchanges were among the earliest fronts for China-U.S. decoupling starting in the late 2010s. Congressional delegations to China declined during Trump’s first term before disappearing amidst China’s COVID-19 lockdown. But Trump’s team formalized that shift by permanently canceling flagship exchanges for congressional staff and other policy leaders. Subnational (city/state/province) exchanges that resumed post-COVID faced aggressive pushback on Capitol Hill and got only tepid backing from the Biden administration.”3. China’s new climate commitmentsWhile the full details of China’s emissions cuts have not been shared yet, the country announced a target of 7-10 per cent cuts in its greenhouse gas emissions by 2035 from its peak levels.UPSHOT: Given the general lack of movement on emissions reduction globally, and the impact of climate change and global warming that are already visible, the scale of cuts was disappointing in some ways. For a detailed analysis of the new announcement, you can read our explainer here.In recent days, China, the Philippines and other parts of East Asia have experienced devastation due to Typhoon Ragasa. As we wrote earlier this week in this explainer, there is a consensus that with rising global temperatures, such tropical cyclones are becoming more intense.Story continues below this adHowever, China’s sheer size means that even small cuts will matter. The announcement follows the country’s previous commitments on the subject, even subtly referencing the US’s backsliding on climate under Trump in official statements. China also leads the way in terms of investments made in green technology and renewable energy.