The baseball cap worn by Francisco "Catfish" Morales (Pedro Pascal) features the logo for Standard Heating Oil the company run by Abel Morales (Oscar Isaac) in the 2014 film A Most Violent Year (2014) also directed by J.C. Chandor.
After Tom Hardy and Channing Tatum left the project over creative changes in the rewritten script, a month later, Ben Affleck and Oscar Isaac took over the respective roles.
Tres Fronteras (Portuguese: Três Fronteiras, English: Three Frontiers) is the Spanish name for an area of the Amazon Rainforest in the Upper Amazon region of South America. It includes, and is named for, the tripoint where the borders of Brazil, Peru, and Colombia meet. The upper Amazon River flows through the area. The Triple Frontier is actually a tri-border area along the junction of Argentina, Brazil and Paraguay.
In April 2017, Paramount decided to not move forward with the project when stars Tom Hardy and Channing Tatum dropped out after disagreements with the rewritten script. The movie was picked up by Netflix a month later. Ben Affleck, who took over from Hardy, later added that another consideration to approach Netflix was that the previous study wanted no Spanish to be spoken in the film, even though the first 20 minutes were exclusively scripted in Spanish; Netflix fortunately had no such reservations.
Some of the cast were trained by real Navy SEALs to make the action appear more authentic.