The italian Renaissance was an artistic movement uneffected by Reformation. In Northern Europe Renaissance was philisphical and strongly affected by Reformation.
Italians divide what most other cultures call Renaissance in two phases: Humanism (Umanesimo) and Renaissance (Rinascimento). The first phase may be started as early as the end of the 14th century. Petrarca was a humanist, Dante a proto-humanist.
Renaissance per se begins with empowering of the bourgeois class in the several Italian state capitals (Florence, Milan, Naples, Rome, Venice, Parma…). The new Seigneurial regimes established new convention with novel partners and new trade tools such as diplomacy, capitalism and banks made their thundering appearance on the political and commercial scene.
Allegoria del Buon Governo (Ambrogio Lorenzetti)
Italian humanism was a cultural/political event linked to the unearthing of thousands of old scripts from ruins and monasteries; related to a strong neoclassic surge, to the printing press, to a new class of cultivated leaders born of the bourgeois class (Medicis, Della Scala, Doria, Dandolo…) rather than of the sword aristocracy.
Italian Renaissance was a cultural/economical event linked to the rapid growth of commerce and trade under the new political structure and the need to express the achievement with public manifestation of pump, good taste and opulence. Michelangelo or Raffaello, Tiziano or Tiepolo would never have painted their masterpieces without the vast sums that popes and doges invested in beautifying their capital cities.
Northern Europe Renaissance is a philosophical movement greatly influenced by Reformation (and counterreformation). Calvin and Spinoza are the two names that come to mind when discussing the reborn Habsburg Empire; Hobbes, and Montaigne when thinking of England and France… as for the artists, as numerous as they were, they all travelled to Italy and learned from the Italian models and masters (Poussin, Cranach, Bruegel, Rubens…)
In Northern Europe the transformation of society that Italy had realised (relatively) peacefully by dispersing and shifting power from aristocracy to bourgeoisie, from agriculture to trade, was a highly conflictual one focussing on personal liberties and individual rights opposed to more and more centralised power in the hands of a few absolute monarchs ready to fight 30 years to maintain their clout.