Games like Tower & Invasion
Games like Tower & Invasion include Total War: WARHAMMER III, Men of War: Assault Squad 2, Total War: WARHAMMER II, Door Kickers, and Call to Arms - Gates of Hell: Ostfront. We matched them by the tags players give Tower & Invasion on Steam (Strategy, Tower Defense, Real Time Tactics, Action, and Simulation): closest matches first, and among equally close ones the better-known games.

Total War: WARHAMMER III
Shared: Strategy · Real Time Tactics · RTS

Men of War: Assault Squad 2
Shared: Strategy · Action · Simulation

Total War: WARHAMMER II
Shared: Strategy · Action · RTS

Door Kickers
Shared: Strategy · Action · Simulation

Call to Arms - Gates of Hell: Ostfront
Shared: Strategy · Real Time Tactics · RTS

Legion TD 2 - Multiplayer Tower Defense
Shared: Tower Defense · Strategy · PvP

Total War: THREE KINGDOMS
Shared: Strategy · Real Time Tactics · RTS

Kingdom Rush - Tower Defense
Shared: Strategy · Tower Defense · Action

Bloons TD 6
Shared: Strategy · Tower Defense · Singleplayer

Totally Accurate Battle Simulator
Shared: Strategy · Simulation · PvP

Infested Planet
Shared: Strategy · Tower Defense · Action

Aliens: Dark Descent
Shared: Strategy · Action · Real Time Tactics

Planetary Annihilation: TITANS
Shared: Strategy · Real Time Tactics · RTS

Creeper World 4
Shared: Tower Defense · Real Time Tactics · Strategy

WARNO
Shared: Real Time Tactics · Strategy · RTS

GemCraft - Chasing Shadows
Shared: Strategy · Tower Defense · Action

Wargame: Red Dragon
Shared: Strategy · RTS · Real Time Tactics

Call to Arms
Shared: Strategy · Action · RTS

Total War: WARHAMMER
Shared: Strategy · Simulation · Real Time Tactics

Mount & Blade II: Bannerlord
Shared: Strategy · Action · Simulation

DG2: Defense Grid 2
Shared: Strategy · Tower Defense · Action

Bloons TD 5
Shared: Strategy · Tower Defense · Action

Creeper World 3: Arc Eternal
Shared: Strategy · Tower Defense · RTS

Ultimate Epic Battle Simulator 2
Shared: Strategy · Simulation · Action