You might be interested in this post by u/itsalrightwithme.

I can't really say much else else about why these changes seem to have originated from the Swiss confederacy in particular, but their tactics were widely copied with varying degrees of success and they were extremely influential, resulting in the sudden reemergence in the pike's popularity as well as the great squares which dominated warfare for most of the 16th century. The most direct result was the German landsknechts, which in the late 15th century hired swiss officers and were essentially built from the ground up to mimic swiss pike tactics.

Arming a militia with pikes and having them stand in defensive line wasn't a difficult task for medieval armies, but ordering them to march, turn, or even charge without losing cohesion was a whole other matter. The Swiss on the other hand were able to turn their pikemen into an extremely powerful offensive force. They did this in part by adopting extremely deep square or column formations, involving up to 60 ranks or more. Since a solid square or column had a much narrower frontage than a line it could advance much more easily without losing cohesion, and once it reached the enemy, the sheer depth meant it was resistant to flanking and had enough mass to bust through their lines and trigger a rout. The second element is that the Swiss adopted a culture of nearly year-round drills and wargames which gave their a militia an extremely high level of proficiency when it came to using their weapons as a group. The Swiss were experts at pulling off complex maneuvers and rapid marches as well as fighting in a deep formation without crowding or literally crushing each other. Though pikemen soon became enormously popular, it was pretty rare to see them perform a lengthy march through wooded hills to surprise the enemy's rear like the Swiss did at the battle of Nancy. While pikemen were still used offensively to varying degrees, as firearms became more effective and more numerous the role of the pike square often returned to being more defensive. When combined with large numbers of shot a pike square served more as a sort of mobile fortress, allowing arquebusiers and musketeers to get close to the enemy where their weapons could do the most damage while also having a refuge in case of a sudden charge by infantry or cavalry.

How do the Spanish Tercios, which had pike formations in them, come to play into this Swiss and Landsknecht story? Where they a later evolution? A separate innovation? A kind of landsknecht?