Blood doping in peloton still exists but is different than in 90s. The Athlete Biological Passport become a tool used to calibrate doping strategy by teams. Blood manipulation methods are more sophisticated as the bio-markers used in ABP can detect anomalies in athlete's blood profile.
This video is based on publications below although presents personal opinion on several subjects.
Publications:
ABP: https://rua.ua.es/dspace/bitstream/10045/17807/6/jhse_Vol_VI_N_II_205-217.pdf
Carsten Lundby - Science of blood doping detection: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3372716/
WADA note about removing default access to ABP profile for an athlete (October 2021): https://adams-help.wada-ama.org/hc/en-us/articles/4407838190738-Why-has-athlete-access-to-ABP-blood-data-been-removed-
Factors confounding ABP: https://sportsmedicine-open.springeropen.com/articles/10.1186/s40798-021-00356-0
Micro-dosing and ABP: https://www.researchgate.net/publication/49851154_Current_markers_of_the_Athlete_Blood_Passport_do_not_flag_microdose_EPO_doping
EPO Micro-dosing and ABP: https://www.researchgate.net/publication/6915012_The_effects_of_microdose_recombinant_human_erythropoietin_regimens_in_athletes
Baesian inference: https://en.wikipedia.org/wiki/Bayesian_inference
Other sources:
https://www.researchgate.net/publication/51171787_Current_limitations_of_the_Athlete's_Biological_Passport_use_in_sports/link/54c2f0380cf219bbe4e9e834/download
https://www.sportsintegrityinitiative.com/french-documentary-alleges-that-micro-doping-can-beat-abp/
https://www.cyclingnews.com/features/are-micro-dosing-riders-poking-holes-in-biological-passport/
https://www.cyclingnews.com/features/tour-de-france-power-analysis-tadej-pogacars-record-breaking-ascent-of-the-col-de-peyresourde/
https://www.youtube.com/watch?v=gqYmJDcPzMM
https://www.youtube.com/watch?v=4uWTgVUmh8A
https://www.youtube.com/watch?v=UmTpHy9oJc8
https://www.cyclingnews.com/features/biological-passport-have-dopers-found-ways-to-beat-it/
https://en.wikipedia.org/wiki/Biological_passport
https://www.raeng.org.uk/RAE/media/Events/Documents/Sports-Engineering-Chris-Cooper.pdf