Shan Wu is a former federal prosecutor who also served as counsel to Attorney General Janet Reno. He practices law in Washington, DC, where he recently defended Rick Gates in the Russian probe. None of the information in this opinion piece utilizes confidential or privileged information. His Twitter handle is @ShanlonWu. The opinions expressed in this commentary are his own.

(CNN) The first trial of Special Counsel Robert Mueller's Russian probe presents multiple challenges to both the prosecution and defense.

The pressure is enormous on both sides.

Mueller's team cannot afford a loss in their very first trial. And a loss for former Trump campaign chairman Paul Manafort, who also faces a second trial in September in Washington, DC, would make defending his second case almost a waste of time.

The charges against Manafort -- tax evasion and bank fraud -- are classic white-collar financial crimes that involve volumes of documentary evidence, including 120,000 documents produced by prosecutors in the last month alone. These kinds of paper-intensive cases often overwhelm white-collar defendants because the data-base management alone can cost thousands of dollars a month and it can be difficult to fight against such a tidal wave of evidence.

But paper evidence does not present itself, and how the prosecution presents and weaves the paper trail into an understandable narrative for the jury can make or break a case.

Here are three critical aspects of the case to pay attention to as the trial gets underway:

Immunized witnesses and Rick Gates

Mueller has sought and obtained immunity for five witnesses -- which is an unusually high number for one trial. The recently revealed names indicate they are mostly financial witnesses who worked on operational day-to-day activities.

At first glance, this might look odd because we are used to the movie portrayal of high-living famous gangsters being given immunity while living in the US Marshal's Witness Protection Program. But the reality is that it is through these less glamorous worker-bee witnesses that the prosecution will admit its evidence and, most importantly, explain the evidence.

Don't expect dramatic revelations from each of these witnesses, but a series of small revelations that the prosecution hopes will be the building blocks of their case. Immunized witnesses typically face cross-examination from defense counsel, focusing on how the immunity gives them an incentive to say anything the government wants. They are seldom very popular with juries but their testimony typically overcomes the distaste most jurors have for them.

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Even though the immunized witnesses lack glamor, their testimony will not lack for drama. Remember these are people who worked closely with Manafort and his deputy, Rick Gates , for a long time. There will be uncomfortable moments for all of them. This will be particularly true when Gates, who has already pleaded guilty and agreed to cooperate, testifies against his former boss, mentor and business partner. Expect fireworks if Manafort's lawyers challenge Gates's truthfulness and integrity as being self-serving.

Will Manafort take the stand?

Most criminal defendants do not take the stand. When I was a prosecutor, I relished the chance to get at a defendant who chose to testify. Any witness on the stand has a hard time withstanding cross-examination because it's the person asking questions who has all the control and any competent prosecutor will score points against all but the most charismatic and able defendants.

But the challenge facing Manafort's lawyers is how to make their client appear sympathetic rather than the American equivalent of a Russian oligarch who also happened to manage Trump's campaign.

Humanizing Manafort to the jury is challenging because pure character evidence is usually excluded as being irrelevant. So evidence of good character -- a hard luck story, a rags-to-riches story, charitable acts -- usually needs to be sneaked in through background questions to witnesses.

Of course, the best witness for Manafort's character would be himself and his defense lawyers will have to think long and hard if letting him testify is the only way to make him more sympathetic to the jury. Expect Mueller's team to be licking their chops at the possibility.

Trump's unspoken presence

The 800-pound gorilla in the room will be President Trump. His influence will be felt even in the jury selection process, as both sides seek to probe whether prospective jurors support or criticize Trump and get rid of them based on these assessments.

Manafort's team wants a jury of Trump supporters and prosecutors want a jury of Trump haters, although of course each side will say they just want a "fair" jury. Concerned about the prejudice of links to Russian collusion and the President , Manafort's team already has filed motions -- motions in limine -- to exclude certain evidence, including the fact that Manafort worked for the Trump campaign

Conversely, Mueller's team has responded in part by arguing they want to introduce evidence of Manafort receiving $16 million in loans from a banker who wanted a job in the Trump administration.