The first (as far as I know) on-screen realistic futuristic combine arms units was seen in 1986's ALIENS. The small United States Colonial Marines rapid response unit that took off from Gateway Station was outfitted with a massive amount of firepower and mobility for such a small unit. If we take from what was shown on screen, this unit of marines had a fully outfitted M577 APC with a number of support weaponry from anti-armor and anti-air, couple this with Hudson exclaims to Ripley.
"I'm ready, man. Check it out! I am the ultimate bad-ass! State of the bad-ass art! You do not want to fuck with me. Check it out! Hey, Ripley, don't worry. Me and my squad of ultimate bad-asses will protect you! Check it out. Independently targeting particle-beam phalanx. WHAP! Fry half a city with this puppy. We got tactical smart missiles, phase plasma pulse rifles, RPGs. We got sonic, electronic ball breakers! We got nukes, we got knives, we got sharp sticks".Then there is the ubercool UD-4 Cheyenne Dropship. The small marine unit is transport from ship-to-shore via a heavily armed dropship that can be used from hot-drops, hot evacs, and for CAS. Within the colonial marine squad, their are flame units, two machines, and riflemen outfitted with grenade launchers. If the marine squad needed to secure a parameter, than they carry four sentry cannons. Very cool. More thought and effort were made in just these few concepts than most author's entire series of books. ALIENS...the best damn MSF film ever!
The Starfist book series
The ISA and Helghast forces from the Killzone Universe