Cap prizes what Peter carries: heart, and a grounded, everyman kind of courage. Spider-Man is the "little guy" Cap has always fought for — the neighborhood hero who saves people because it's simply the right thing to do. They've stood side by side in the Avengers, and once even faced off across a super-hero civil conflict before reconciling. The respect outlasted the disagreement.
Spider-Man and Captain America first shared the page in Amazing Spider-Man Annual #3 (1966), when the Avengers — Cap among them — considered Spidey for membership and set him the test of capturing the Hulk (he ultimately walked away, deciding he wasn't team material). An early direct encounter came in Captain America #137-138 (1971), where Spider-Man guest-starred and Cap and the Falcon initially took him for a menace. Their first one-on-one team-up was Marvel Team-Up #13 (1973). Over the following decades this grew into a long mentor-and-protege dynamic.
Steve Rogers is once again the primary Captain America, and he and Spider-Man remain steadfast allies with deep mutual respect — Cap functions as a mentor and father-figure whom Peter Parker holds in higher regard than almost anyone. Having served together across the New Avengers era and Marvel's major events, they continue to cross paths in Avengers and event storylines. The Civil War rift is long healed; their modern relationship is defined by trust, with Cap one of the few heroes Spider-Man will unhesitatingly follow into a fight.
Steven "Steve" Rogers was a frail young man with more courage than muscle when the WWII Super-Soldier Serum transformed him into a peak-human super-soldier. He became a symbol as much as a fighter — until an accident left him frozen in ice for decades, to be revived into the modern age a man out of his own time.
He carries peak human strength, speed, agility and endurance, but his real edge is his mind: a master tactician and hand-to-hand combatant who leads from the front. In his grip, a near-indestructible vibranium shield becomes offense, defense, and rallying point all at once.