You have to go back over a decade to find the last time New Orleans Saints didn't pick a lineman in the first round. Chris Olave is the last non-offensive or defensive lineman the Saints have drafted in the first round, but he had to share the round with Trevor Penning the same way Marshon Lattimore shared the distinction with Ryan Ramczyk in 2017.
You have to go all the way back to 2014 when the Saints Brandin Cooks in the first round to find a year where the Saints didn't invest in the trenches in Round 1.