Defensive alignments, when to pull the pitcher, who to start in the lineup, match-ups, pitch selection, how to attack the hitter, situational hitting, when to call a hit a run or bunt, when to steal a base depending on whos pitching and catching.
There is way more as well.
I played baseball at a fairly high level for almost 2 decades of my life, so believe me when I say there is a lot of strategy in Baseball