One cloud software stock is soaring above the rest so far this year.

Box shares have rallied 38 percent in 2019, well above the advances of less than 20 percent for Workday, Adobe and Salesforce.com.

Its massive run has one trader wary of a possible pullback from here.

"It's getting very overbought on a short-term basis," said Matt Maley, equity strategist at Miller Tabak, on CNBC's "Trading Nation" on Tuesday. "The RSI chart at the bottom, it's up almost 50 percent in just five weeks. So my thinking is that you don't want to chase it up here, let it pull back a little bit."

Box's recent gains have pushed its relative strength index close to 77, above the 70 threshold that generally delineates normal from overbought conditions.

However, on a longer-term basis, Maley says the cloud software stock should continue to perform well.

"It made a great double bottom back in the fourth quarter, and it bounced off its trend line going back to the 2016 lows," said Maley. "It's rallied today above its 200-day moving average. ... The stock looks great on a long-term basis."

Box popped back above its 200-day moving average on Tuesday after breaking below it back in October. It trades 4 percent above that long-term trendline.

From an options perspective, it looks as though some investors are cashing in on Box's solid start to the year, according to Stacey Gilbert, head of derivative strategy at Susquehanna. Options traders are dealing with the rest of the space on a case-by-case basis.

"If we take a step back and just look at the broader cloud space, it's actually quite mixed, and this is much more consistent with what we've seen in the market as a whole," Gilbert said on "Trading Nation" on Tuesday. "It seems as if the market is taking a much more active approach to its investing; it's not as passive."

If Gilbert were to pick one stock involved in cloud computing, she sees a clear winner.

"We definitely look towards Amazon for the cloud exposure relative to some of the other names," said Gilbert. "We think it's a game changer over the next 10 years, plus you're getting two other big growth segments here within Amazon – this is obviously going to be e-commerce and advertising."

Amazon has risen 9 percent so far this year, around a quarter of Box's gains. Over the past 12 months, it has risen 14 percent, higher than Box's 13 percent increase.