Robust first-quarter earnings stateside and seemingly favorable developments on the Korean Peninsula last week may have painted a rosy picture ahead for markets, but staying cautious could prove to be a smart move for investors.

"Our base case is fairly positive, but still, the fact is that we are seeing markets have relatively weak momentum," Mikio Kumada, executive director and global strategist at LGT Capital Partners, told CNBC's "Capital Connection."

"Even though we have strong earnings, the market is not gaining momentum and we have some of the economic data in the U.S., as well as Europe, being still positive, but showing some slowdown. So that suggests the market is a little bit skeptical," he added.

This earnings season has been robust, with close to 80 percent of the 276 S&P 500 companies that had reported as of Friday topping analyst expectations, according to Thomson Reuters I/B/E/S. Earnings in the first quarter are projected to rise 24.6 percent compared to a year ago.

Largely upbeat earnings releases have buoyed U.S. stocks, although markets stateside finished little changed on Friday.

"This is a tricky phase, where the sentiment, because of the trade war, affected the markets, and the markets may start to affect the real economy, so I think a little bit of caution is warranted here," Kumada said.