The setting: Every relevant part of the world is bathed in a thick, soupy, magic juice fog (visibility hovers around a hundred meters on most days). Among other effects, it makes firearms extremely unreliable and short-ranged: your average M4 has an effective range of maybe 50 meters and often jams at least once every magazine, most .30 caliber rifles can reach out to 75 meters and pistol rounds rarely spit past 20 or 30most .30 caliber rifles can reach out to 75 meters and pistol rounds rarely spit past 20 or 30. Heavy weapons are more reliable, but even more gimped in range: past 300-ish meters, most howitzers become pointlessly inaccurate, and even the best tank guns rarely hit past 200 meters. The environment is mainly made up of endless deserts, dotted with ruined old world towns and extensive trenchlines dating back to the start of The War(tm).
(EDIT) Due to a multitude of reasons, most infantrymen can only throw grenades up to around 20-30 meterscan only throw grenades up to around 20-30 meters, and their lethality is somewhat hampered (10-ish meters of wounding radius). Same goes for other ordnance - a mortar shell is mostly harmless after 25 meters, a 30mm HE shell can wound up to 6 meters away, a 75mm can maybe do 20. Bows and crossbows have fairly good range, roughly comparable to a full-power battle rifle, but due to their low firerate and ease of use I can't see them being too popular with line infantry. Vehicles are a mixed bag - generally, if the most complicated piece of electronics in it is a spark plug or a headlight, it'll be fine, but on-board computers or advanced sensors require very expensive shielding to not fry in the fog (Red can do this for much lesser expense though). Thermal imaging does function, though with very limited range (good optics, like those mounted on Red tanks, can see up to maybe 200 meters) and price is still multiplied by the need for expensive shielding - same goes for radar, though sonar fares a little better. Factoring in the shielding, though, neither are compact (or accurate) enough that they would be relevant for a standard infantryman.
(EDIT 2) This is a very hot, bloody conflict. I apologize if my request for simply squad-level tactics was misleading but, in retrospect, it's quite likely - considering the troop densities and level of entrenchment - that most scuffles would escalate quite drastically, pulling in fire from neighboring units and generally just making straightforward bayonet rushes or flanking maneuvers not always practical. Actual fighting in the open desert isn't terribly common and is mostly left to vehicles - if infantry is being deployed, at very least there will usually be a trenchline or forward operating base to assault.