About inserting the symbol lambda into the paper.md

[xiki-tempula]

Hi, sorry I don't know if this is the right place to post this question. I'm interested in inserting the lambda symbol as an inline equation.

a parameter lambda ( $\lambda $ )

However, I got

Latexmk: ====List of undefined refs and citations:
  Missing character: There is no 𝜆 (U+1D706) in font [NewCMSans10-Book.otf]:mode=node;script=latn;language=dflt;+tlig;!
[makePDF] Run #1
Rc files read:
  NONE
Latexmk: Run number 1 of rule 'lualatex'
This is LuaHBTeX, Version 1.15.0 (TeX Live 2022) 
 restricted system commands enabled.
Latexmk: Getting log file '/tmp/tex2pdf.-6dcaa6318cd2907b/input.log'
Latexmk: Run number 2 of rule 'lualatex'
This is LuaHBTeX, Version 1.15.0 (TeX Live 2022) 
 restricted system commands enabled.
Latexmk: Getting log file '/tmp/tex2pdf.-6dcaa6318cd2907b/input.log'
Latexmk: Summary of warnings from last run of *latex:
  =====Latex reported missing or unavailable character(s).
=====See log file for details.


[WARNING] Missing character: There is no 𝜆 (U+1D706) (U+1D706) in font [NewCMSans10-Book.otf]:mod

The symbol lambda is a widely used symbol and I'm sure that there is a way of inserting this as an inline equation, I wonder if I could get some help with regard to how to insert this symbol, please? Thank you.