This repo contains the installation guide and EFI files required to get a perfectly functional Catalina 10.15.7 hackintosh on your T450. Everything is stable and functional as described in this Readme

Original Readme from Echo:

Thinkpad T450s Catalina

Notice: If you need to edit config.plist, don't use OpenCore configurator, use PlistEdit pro or Xcode instead.

Introduction

efi for Thinkpad T450s (20BXCT01WW) Hackintosh Catalina.

CPU: i5-5200U

Integrated Graphics: HD Graphics 5500

Sound Card: ALC292

Wireless Card: DW1820A 00JT494

Bios

Security -> Security Chip: Disabled;
Memory Protection -> Execution Prevention: Enabled;
Virtualization -> Intel Virtualization Technology: Enabled;
Internal Device Access -> Bottom Cover Tamper Detection: must be Disabled;
Anti-Theft -> Current Setting: Disabled;
Anti-Theft -> Computrace -> Current Setting: Disabled;
Secure Boot -> Secure Boot: Disabled;
UEFI/Legacy Boot: UEFI Only;
CSM Support: Yes.

What works

Sleep / Wake
Wifi and Bluetooth (DW1820A)
Handoff, Continuity, AirDrop
iMessage, FaceTime, App Store, iTunes Store (Change Config.plist -> PlatformInfo -> Generic -> MLB and SystemSerialNumber)
Ethernet
Onboard audio (Use alc_fix to fix unworking jack after replug )
USB 2.0 / USB 3.0
Battery
Touchpad
Redpoint
miniDP
SD Card Reader (Thanks to @willmav5000)
Use one-key-hidpi to enable HiDPI
If you are using a usb mouse with side buttons, you can spoof apple usb mouse by change the pid and vid in AnyAppleUSBMouse.kext/Info.plist and enable it in config.plist.

What doesn't work

VGA
Sidecar (Wired Sidecar works but only in Macbook9,1 SMBIOS, which has bad battery life, you can choose what you want)