Don't time the market
Every time there's some risk that could cause stocks to halve (or lose more of) their value. Most of the time, it won't happen. I'm sure you won't find any period where negative news don't exist. You just need to learn to ignore negative news.
Instead, invest as much into stocks as you are comfortable
Stocks yield more than bonds. In the long run, the yield is certain to be more. In the short run, bonds may temporarily outperform stocks. For example, in 30 years in the worst case stocks yield 8% per year then fall by 80% due to a market crash, or 1.0830*0.2 = 2.0125 times. Where I live, AAA bonds have a slightly negative yield. Actually, even for 20 years stocks yield 1.0820*0.2 = 0.93219 times in the worst case, and bond yield is -0.179% per year or (1-0.00179)20 = 0.96480. So, bit over 20 years and you are almost guaranteed to outperform bonds in the current market situation.
Note the 80% crash is the worst case scenario, taken from the Great Depression effect on stock prices. It happened only if you invested all your money immediately into stocks at the highest price, then withdrawed your money approximately at the worst possible moment.
I would say if your time horizon is less than 20 years, and you don't like losing much money, some percentage of AAA bonds in your portfolio could be a good idea if they have a positive yield. (If they have a negative yield and you have the possibility to store your money in a bank account with zero yield, use the bank account instead!)
For example, for retirement savings your horizon is likely over 20 years unless you plan to retire very shortly or you have a fatal disease causing you to die at an early age. For saving for a newborn child, your horizon is likely over 20 years too.
For saving towards a short-term target like purchasing a house (hint: don't spend a lot of money to purchase an expensive house!) you probably want to include lot of AAA bonds in your portfolio.
Diversify away your risk
Some stocks benefit from the trade war, some are negatively affected by the trade war. On the average, the trade war probably has a slightly negative effect. If you diversify your stock holdings, you won't have only those stocks that lose a lot of value due to the trade war.
Remember your trading fees
Every time you trade stocks, you lose and the stock broker wins. Don't trade unnecessarily!